,transcriber's ,note3 ,minor typographical errors have been corrected without note4 ,irregularities and inconsistencies in the text have been retained as printed4 ,words printed in italics are marked with underscores3 italics4 ,words printed in bold are marked with tildes3 bold4 ,a caret 77 is used to indicate that the following character is printed as a superscript4 ,illustration3 ,photograph and written signature of ,william ,robinson ,,the ,,invention ,,of ,,the ,,track ,,circuit ,,the ,,history ,,of ,,dr4 ,,william ,,robinson',s ,,invention ,,of ,,the ,,track ,,circuit ,,the ,,fundamental ,,unit ,,which ,,made ,,possible ,,our ,,present ,,automatic ,,block ,,signaling ,,and ,,interlocking ,,systems ,,signal ,,section ,,american ,,railway ,,association ,,new ,,york #aibb ,,preface ,believing that no more fitting memorial can be prepared in honor of ,dr4 ,william ,robinson than to reproduce the salient points relating to his great achievement as written and published by himself in #aijf under the title of ,history of ,automatic ,electric and ,electrically ,controlled ,fluid ,pressure ,signal ,systems for ,railroads1 the committee has accordingly drawn largely from this pamphlet for the material contained in ,part ,i4 ,part ,,ii is devoted to ,w4 ,a4 ,baldwin1 formerly ,general ,superintendent of the ,pennsylvania ,railroad1 who was responsible for the first installations of automatic block signals controlled by track circuits4 ,as this memorial would not be complete without a description of the track circuit1 its principle and operation under present day signaling practices1 ,part ,,iii is accordingly devoted to this subject4 ,,herbert ,s4 ,,balliet1 ,chairman2 ,,keith ,e4 ,,kellenberger1 ,,henry ,m4 ,,sperry1 ,committee4 ,,contents ,,resolution #a ,i ,,the ,,invention ,,of ,,the ,,track ,,circuit #c ,robinson's ,patent #db ,robinson's ,description of ,his ,invention #ej ,dr4 ,robinson's ,record1 ,wesleyan ,university #ei ,dr4 ,robinson's ,record1 ,a4,i4,e4,e4 #fj ,,ii ,,william ,a4 ,,baldwin #fh ,,iii ,,the ,,track ,,circuit #gf ,its ,principle #gg ,its ,characteristics #he ,the ,extent of its ,use #ih ,,iv ,,the ,,track ,,circuit ,,in ,,great ,,britain ,,and ,,on ,,the ,,continent1 ,,by ,t4 ,s4 ,,lascelles #ajc ,some of the ,first ,installations #ajf ,track ,circuits on the ,continent #aji ,,the ,,track ,,circuit#a ,perhaps no single invention in the history of the development of railway transportation has contributed more toward safety and despatch in that field than the track circuit4 ,by this invention1 simple in itself1 the foundation was obtained for the development of practically every one of the intricate systems of railway block signaling in use today wherein the train is1 under all conditions1 continuously active in maintaining its own protection4 ,in other words1 the track circuit is today the only medium recognized as fundamentally safe by experts in railway signaling whereby a train or any part thereof may retain continuous and direct control of a block signal while occupying any portion of the track guarded by the signal4 #a ,from the ,third ,annual ,report of ,the ,block ,signal and ,train ,control ,board to the ,interstate ,commerce ,commission4 ,dated ,nov4 #bb1 #aiaj4 ,resolution ,adopted at ,annual ,meeting of ,signal ,section1 ,a4,r4,a4 ,chicago1 ,june1 #aiba ,,whereas1 ,almighty ,god1 in the exercise of ,his ,divine will1 has removed from this world our late honorary member1 ,dr4 ,william ,robinson1 and1 ,,whereas1 ,dr4 ,robinson1 well called the father of automatic block signaling because of his basic invention of the closed track circuit ,august #bj1 #ahgb1 began the development of an automatic signal system in #ahfg and installed the so-called open circuit system at ,kinzua1 ,pa41 on the ,philadelphia ,erie1 now the ,pennsylvania ,railroad1 in #ahgj1 and1 ,,whereas1 he worked on the development of fiber for insulated rail joints in #ahgf and also developed the channel pin about the same time1 and1 ,,whereas1 one of the first signals controlled by more than one track circuit was installed under his direction at the ,tehauntepec tunnel in ,california in #ahgg1 and1 ,,whereas1 his death at ,brooklyn1 ,n4,y41 on ,january #b1 #aiba1 at the age of #hj1 is an irreparable loss to the ,association4 ,,therefore1 we1 members of the ,signal ,section1 ,american ,railway ,association1 pay our last sad tribute to his memory and express our deep appreciation of the many and lasting obligations that our members and friends owe to him1 and by words and outward token express our sincere sorrow for the irreparable loss the ,association has sustained4 ,,therefore1 be it ,resolved1 that a fitting memorial to the memory of ,dr4 ,william ,robinson1 commemorating the #ejth anniversary of his invention of the closed track circuit1 be prepared and presented to this ,association at the ,annual ,meeting in #aibb4 ,resolved1 that these resolutions be spread upon the records of the ,association4 ,,the ,,invention ,,of ,,the ,,track ,,circuit ,about #ahfg ,william ,robinson1 then a recent graduate from college1 entered actively upon the development of an automatic signal system for preventing accidents of various kinds on railroads4 ,his attention was called to the subject by the consideration of certain railroad accidents which had occurred1 and for the prevention of which there were no adequate means known4 ,from this starting point he developed such a system1 and in #ahfi1 constructed an elaborate model illustrating the same1 which he exhibited at the ,american ,institute ,fair in ,new ,york ,city1 in #ahgj4 ,this system was what is now known in the art as a wire or open circuit system2 that is1 there were circuit-instruments in proximity to the track which were actuated by the wheels of a car4 ,the action of the wheels on a lever at one point closed the circuit through a relay1 whose magnet was so arranged that the instant it was magnetized it attracted its armature and kept its own circuit closed4 ,the circuit of the magnet which directly actuated or controlled the signal was under control of the relay1 which operated to open and close the signal circuit directly4 ,when the train or car proceeded to the proper point beyond1 it actuated a reversing lever1 thus opening the relay circuit and reversing the signal4 ,in the model described the reversing lever operated to open the relay circuit by cutting off the battery therefrom by short circuiting4 ,this model was in continuous and perfect operation throughout the duration of the fair4 ,at the close of the fair ,mr4 ,robinson had some of his descriptive circulars left over4 ,these he immediately sent out to railroad companies at random4 ,one of these circulars1 at least1 was as seed sown in good ground4 ,it elicited an immediate response from ,mr4 ,william ,a4 ,baldwin1 general superintendent of the ,philadelphia and ,erie railroad1 with the result that ,mr4 ,baldwin1 who was an old telegraph operator and a very able and progressive railroad man1 on looking into the system was so impressed with its practicability and importance that he at once arranged with ,mr4 ,robinson to make an installation of the system on his road4 ,this was in #ahgj4 ,at that time ,mr4 ,theodore ,n4 ,ely1 now chief of motive power 7#aijf7 of the ,pennsylvania railroad1 was assistant superintendent of the ,philadelphia ,erie1 and1 under direction of ,mr4 ,baldwin1 furnished ,mr4 ,robinson with all the facilities and material necessary for prosecuting the work of installation4 ,this installation was made at ,kinzua1 ,pa41 and after a little experimenting was soon in perfect working order1 performing all claimed for it1 and considered satisfactory by the railroad company4 ,this was a normally open-circuit wire system1 however1 controlled by track levers1 as above described1 in connection with the model4 ,as soon as it was found to be working perfectly and accomplishing all claimed for it1 ,mr4 ,robinson1 who aimed to be the most severe critic of his own work1 entered systematically into a deeper study of the system from the standpoint of a railroad man1 with a view of finding the weak points in it1 if any existed4 ,he soon discovered the following serious defects1 which are inherent in all normally open circuit or wire systems of automatic signaling1 without exception4 ,such systems are extremely limited in their functions1 and may1 under certain circumstances1 show a ,,safety signal when the danger actually exists which they are designed to avert1 as in the following cases3 ,first3 ,a train enters regularly upon the section and sets the signal at danger2 the train breaks in two1 the forward part passes off the section1 reverses the signal and shows ,,all ,,clear behind that portion of the train remaining on the section2 and a following train1 lured on by the false signal ,,all ,,clear1 dashes into the stalled portion of the preceding train left standing on the section4 ,this is extremely liable to happen on sharp curves and grades1 where breaks are not of uncommon occurrence4 ,second3 ,a train may enter within the section from the opposite end or from a siding1 thus blocking the track1 while the signal1 not having been affected1 shows ,,all ,,clear as before1 a false signal again4 ,third3 ,if a line wire break or other connection be interfered with accidentally or maliciously1 or the battery fail from any cause1 the signal will invariably show ,,all ,,clear1 under every train passing over the section1 a false signal again4 ,mr4 ,robinson at this early date recognized the above serious objections as inseparable from open circuit system of signaling1 apparently1 before these defects were recognized by any one else1 and at once entered upon the solution of the problem presented1 of eliminating these objections by producing a signal system which would meet all the requirements of safe and efficient railroading4 ,he reasoned1 first1 that to accomplish this result every car and every pair of wheels in the train must have controlling power over the signal throughout every inch of the block section1 and second1 the signal should go to danger by gravity1 the electric current being used to hold it at safety4 ,could these two results be accomplished8 ,could the rails be used in any way to carry the primary current in a reliable manner8 ,manifestly not by any open circuit means1 for the reason that sections of rails of even moderate length1 on open circuit1 would form a good ground1 especially in damp or wet weather1 thus keeping the circuit closed continuously and preventing any operation of any kind4 ,he at once cast aside this open rail circuit idea as fruitless1 and having previously1 in #ahfi-gj1 used the short circuiting principle in his model1 as above stated1 he concluded that this principle presented the only possible solution of the problem4 ,he then made drawings of the closed rail circuit system substantially as it is used today1 and in #ahga applied for a patent thereon1 broadly covering the closed rail circuit system4 ,in #ahgb he made an exhibition of this system at the ,state ,fair1 held at ,erie1 ,pa4 ,here he placed a large gong on the end of one of the buildings1 on the outside1 and inside he had a track made in sections placed in a long water tank made for the purpose4 ,the track was covered several inches deep with water and the running gear of the car model was similarly immersed4 ,the system was connected on the short circuit principle through the rails4 ,wires connected the gong with the back contact of the track relay4 ,the water had no perceptible effect on the operation of the apparatus1 and when the car was run on the signal section it short circuited the current from the relay1 which1 releasing its armature1 closed circuit through its back contact and thus through the magnet of the gong circuit1 thus setting the gong ringing loud enough to be heard all over the grounds4 ,on running the car off the section the current returned to the relay energizing the same and thus opening the gong circuit at the back contact of the relay1 thereby causing the gong to cease ringing4 ,the whole operation was perfect1 demonstrating the successful operation of the closed circuit system1 and attracted great crowds of people as well as the marked attention of practical railroad men4 ,it will be understood1 of course1 that the local circuit may be normally open as above described and used1 or normally closed as now commonly used1 according to the exigencies or requirements1 or preferences of the parties using the same1 and when desired1 a visual signal may be substituted for the audible signal above described4 ,these are all minor details not involving separate invention4 ,mr4 ,robinson had previously explained the new closed rail circuit system to ,mr4 ,baldwin1 who was greatly interested and expressed his confidence in it and requested ,mr4 ,robinson to install the system at ,kinzua1 where he had already installed the open circuit wire system4 ,illustration3 ,fig4 #a4 ,robinson's ,closed ,rail ,circuit ,system4 ,philadelphia ,erie ,railroad1 #ahgb4 ,as all the signal apparatus1 relays1 batteries1 office switches and overlapping devices were already in operation there1 it took but a short time to convert this open circuit system into a closed rail circuit system4 ,the first experiments proved conclusively that the system would work4 ,the track1 however1 was in a fearfully unsuitable condition for the purpose4 ,the light rails were fished together by a four foot wooden bar on the outside1 and a twelve inch fish plate on the inside4 ,there were two holes through the iron fish plate1 allowing one bolt for each rail and four holes through the wooden bar1 two for each rail4 ,however1 with a little care he managed to get the current working through the whole length of the section about a mile and a quarter in length4 ,it was evident1 however1 that on such a section as this a rail bond of some kind would be necessary for reliable1 continuous service1 and here1 at this time1 in #ahgb ,mr4 ,robinson conceived the invention of the bond wire method of electrically connecting the rails1 now in universal use1 or its equivalent1 on every electric railway throughout the world using the rails for a return4 ,as it had been determined to lay new rails at ,kinzua1 another installation of the closed rail circuit system was ordered and immediately made at ,irvineton1 ,pa4 ,this signal is illustrated in ,fig4 #a4 ,it will be observed that the above installation1 like that at ,kinzua1 not only displays a visual block signal1 but also operates in connection therewith a loud gong which has been easily heard at a distance of a half mile1 and was really heard by passengers in trains passing1 with closed windows4 ,an engineer could not possibly pass without hearing it4 ,a wire is seen at the upper part of the signal box1 running out to the right4 ,this is an overlapping signal wire4 ,a tell-tale bell was also placed in the station1 indicating the actual position of the signal1 and also a manual switch1 whereby the agent could at any time cut off or short circuit the track battery and expose the danger signal against a train and instantly receive a return signal when the danger signal was actually exposed4 ,the ,irvineton installation worked perfectly from the first never failing4 ,the locomotive engineers were delighted with it and soon gave it the name of ,the old reliable4 ,illustration3 ,,the ,,robinson ,,closed ,,rail ,,circuit4 ,fig4 #b4 ,wm4 ,robinson1 #ahga1 ,patented in ,france1 ,february #bi1 #ahgb1 and ,united ,states ,august #bj1 #ahgb4 ,re-issued ,july #g1 #ahgd4 ,no4 #eieh4 ,the ,robinson closed rail circuit1 which now forms the basis1 according to the best information1 of every efficient automatic electric1 electro-pneumatic and electrically controlled fluid pressure system throughout the world1 is illustrated in its simplest form1 in ,fig4 #b4 ,this figure shows the railroad track divided into sections1 a mile more or less in length1 the section rails being insulated from adjacent sections4 ,a light battery has its terminals connected to the opposite rails at one end of the section and at the other end a relay magnet has its terminals connected to the opposite rails4 ,thus the current passes through the whole length of the section1 keeping the relay on continuously closed circuit and magnetized as its normal condition4 ,the relay thus keeps the secondary circuit1 which directly controls the signal1 normally closed1 whereby the signal is normally held in a position indicating safety4 ,when a train enters upon the section1 the wheels and axles1 connecting the opposite rails thereof1 short circuit the current from the relay1 which instantly releases its armature1 thus opening the signal circuit4 ,the signal is then instantly thrown to the danger position by means of a counterbalance4 ,the signal may be of the enclosed disk type1 electro-mechanical1 electro-pneumatic1 electrically controlled gas1 or of any other kind4 ,the ,robinson patented system is broad1 basic and a generic creation2 it is not limited to any specific construction or arrangement of signal but covers all kinds4 ,in expounding the early history of the art of automatic signaling1 the following photographic reproductions from some of ,robinson's early circulars and patents will be of interest4 ,the following sections on ,,curve1 ,,tunnel1 ,,station1 ,,switch and ,,draw-,,bridge ,,signals are a photographic reproduction from a circular issued by ,mr4 ,robinson in #ahgj3 ,,curve ,,and ,,tunnel ,,signals4 ,a train approaching a curve will throw up a red signal around the curve as a warning to trains from the opposite direction1 and will also exhibit a signal in its rear4 ,thus1 collisions from front or rear are guarded against4 ,these signals may be used throughout the whole extent of a road4 ,in entering a tunnel a train will exhibit a signal at the other end to indicate its entry1 and when it gets through it will lower the signal and ring a bell at the opposite end to indicate its exit4 ,,station ,,signals4 ,a train when it leaves a station1 and at various points as it passes1 will indicate to the stations along the line1 its ,location1 ,direction1 ,rapidity and ,length4 ,thus all necessary information regarding moving trains will be automatically announced every few minutes at the stations4 ,,switch ,,and ,,draw-,,bridge ,,signals4 ,if a switch or draw-bridge is misplaced an approaching train will set an alarm ringing at the station and will also exhibit a red signal ahead of the train as a warning to the engineer that the switch is misplaced4 ,the following heading and sections are photographic reproductions of parts of a circular issued by ,mr4 ,robinson at the time of its date1 ,september1 #ahgb4 ,it will be observed that certain of these sections are the same as above reproduced from the circular of #ahgj4 ,it will be noted also that the description of the system begun after the heading is not here completed1 for the reason that a full description is found elsewhere in this history4 ,,robinson',s ,,improved ,,systems ,,of ,,electric ,,railway ,,signals ,for ,switches1 ,draw-bridges1 ,crossings1 ,curves1 ,cuts1 and ,tunnels2 also1 to indicate the ,location1 ,direction1 ,rapidity1 and ,length of ,trains4 ,,important ,,improvements4--,,electric ,,signaling ,,without ,,track ,,instruments1 ,,or ,,line ,,wires4 ,,the ,,new ,,system4 ,the operation of this system is as follows3 ,a railroad track is divided into sections of any desired length1 say one mile1 more or less1 by separating the abutting rails from metallic contact with the adjacent sections1 but preserving metallic continuity throughout the length of the section4 ,the insulation of the abutting rails is accomplished ,,curve ,,and ,,tunnel ,,signals4 ,a train approaching a curve throws up a red signal around the curve1 as a warning to trains from the opposite direction1 and also exhibits a signal in its rear4 ,thus1 collisions from front or rear are guarded against4 ,these signals may be used throughout the whole extent of a road4 ,in entering a tunnel a train exhibits a signal at the other end to indicate its entry1 and when it gets through it exhibits a signal at the opposite end to indicate its exit4 ,,station ,,signals4 ,a train when it leaves a station1 and at various points as it passes1 indicates to the stations along the line1 its ,location1 ,direction1 ,rapidity1 and ,length4 ,thus all necessary information regarding moving trains is automatically announced every few minutes at the stations4 ,the batteries for operating the signals will last for months without attention1 and one man can readily attend to all the signals and batteries throughout the whole extent of a road4 ,in all cases1 where practicable1 the signal wire should be carried through the coils of a bell-magnet in the nearest office4 ,by this means the operator is informed when the battery power is decreasing1 and warned that it requires renewing4 ,office connections can be made1 when desired1 so that the signals may be operated by a telegraph key from the office1 as well as by passing trains4 ,the signal wires may be tapped at intervals all along the line1 and led into small cast iron boxes placed conveniently on the telegraph poles4 ,conductors of all trains1 furnished with keys to these boxes1 can1 in case of special accident1 go to the nearest box1 touch a key within the same1 and thus set danger signals at some distance in front and rear of their trains4 ,the telegraph keys in these boxes not only set the danger signals as described1 but they also place the said signals1 for the time being1 entirely out of control of moving trains4 ,,the ,,closed ,,circuit4 ,the new system1 as described1 with closed circuit1 is the best ever devised for block-signaling1 since the failure of the battery through neglect or otherwise1 cannot possibly be productive of disastrous results to the train1 however implicitly the signals may be relied on4 ,from the ,french of ,feb4 #ahgb ,translation4 #hhth claim4 ,connecting a battery ,b#e1 and a magnet ,m#e with the rails a#i1 b#i1 of a section of railroad track ,c#e in such a manner that when said rails are joined by a metallic bridge1 the electric current will be diverted from the magnet ,m#e1 but so that when said bridging device is removed from said section ,c#e the electric current will be free to pass through and charge the magnet ,m#e4 #ic;d4 ,a signal or signals audible or visual in combination with the battery ,b#e and the rails of a railroad track1 the whole being arranged to actuate the signal or signals1 substantially as described4 ,,william ,,robinson4 ,,st4 ,,petersburg1 ,clarion ,county1 ,pa41 ,september1 #ahgb4 ,it will be observed that some of the foregoing sections refer to the open circuit system1 some specifically to the closed circuit system and some are applicable to either or both4 ,the following is a photographic reproduction of a postal card issued and distributed broadcast by ,mr4 ,robinson at the time of its date1 ,may1 #ahgc4 ,it needs no comments4 ,,robinson',s ,,wireless ,,electric ,,signals1 ,,the ,,simplest1 ,,cheapest1 and ,only ,absolutely ,,safe ,electric ,signals in ,existence1 ,,now ,,in ,,successful ,,operation ,,on ,,the ,,baltimore ,,and ,,ohio1 ,,phila41 ,,wilmington ,,baltimore1 ,,philadelphia ,,and ,,erie1 ,,and ,,other ,,rail ,,roads4 ,they work as ,,automatic ,,blocks with tell-tale alarms1 ,,office1 ,,station1 ,,road ,,crossing and ,,switch ,,signals1 and ,,broken ,,rail ,,detectors4 ,these signals have worked uninterruptedly through last winter regardless of rain1 snow1 slush or sunshine4 ,descriptive circulars on application4 ,,may #ahgc4 ,,wm4 ,,robinson1 ,st4 ,petersburg1 ,pa4 ,illustration3 ,fig4 #c4 ,illustration from ,robinson's ,circular of ,january1 #ahgd1 showing the ,closed ,rail ,circuit1 ,relay and ,overlapping ,system4 ,it is pointed out that the above illustration of ,january1 #ahgd1 shows the ,robinson closed track circuit1 as heretofore described1 the relay ,r and the track battery ,i forming a part thereof1 the signal actuating magnet ,e1 the signal ,c operated thereby1 the circuit wires of said magnet ,e connected to1 and controlled by1 the relay ,r1 and the overlapping or distant signal ,l1 with its circuit ,h controlled absolutely by the position of the signal ,c1 the whole showing a complete closed track circuit overlapping system1 with home and distant signals4 ,the following sections are from this circular of ,january1 #ahgd3 ,when it is desired to operate a secondary signal thrown forward or back of the primary1 a line wire ,h is used1 attached to the primary signal ,c in such a way that the secondary signal cannot possibly operate unless the primary signal ,c is first exposed1 thus closing circuit on the wire ,h4 ,the primary signal battery ,k is used to operate the secondary signal4 ,to set the signal from an intermediate station a wire from each rail of the section ,a is run into the station4 ,when these wires are connected by a key1 the current from the battery ,i is placed on short circuit1 and the signal exposed as before4 7,see ,fig4 #g47 ,the following functions may be embraced in the signals of a single section4 ,,block ,,signaling1 both automatic and manipulated1 ,,switch1 ,,drawbridge1 ,,road-,,crossing1 and ,,station-,,approach ,,signaling1 and ,,broken ,,rail ,,detecting4 ,in this system it will be observed that1 since the signal is exposed mechanically1 any tampering with the rails or connections1 or failure of the battery1 will invariably result in exposing the signal2 any error therefore which may occur from any cause will be in behalf of safety4 ,it is impossible to show safety when the danger exists which the signal is designed to avert4 ,during the early seventies ,mr4 ,robinson made other closed rail circuit installations on the ,philadelphia ,erie and other railroads in ,pennsylvania and ,maryland4 ,visit of the ,pennsylvania ,r4,r4 ,officials ,on ,october #bd1 #ahgc1 a special inspection train of the ,pennsylvania railroad passed over the ,philadelphia ,erie railroad1 westward4 ,the ,pennsylvania ,r4,r4 officials aboard were3 ,mr4 ,a4 ,j4 ,cassatt1 at that time general manager2 ,mr4 ,gardner1 general superintendent2 ,mr4 ,lewis1 controller2 ,mr4 ,robert ,pitcairn1 superintendent western division1 and ,mr4 ,frank ,thomson1 superintendent motive power4 ,mr4 ,wm4 ,a4 ,baldwin1 general superintendent of the ,p4 ,e4 road1 was of the party1 and ,mr4 ,robinson joined the party on the latter road1 and continued with it through to ,erie1 which was reached in the evening4 ,stops were made at ,ridgway on the ,middle division and at ,irvineton on the ,western division to examine the ,robinson closed circuit rail system of signals1 which were in full operation at those points4 ,a thorough examination and various tests were made1 to all of which the signals responded promptly and perfectly4 ,the following is from a letter by ,mr4 ,robinson to his brother on ,october #be1 #ahgc3 ,mr4 ,baldwin could not say enough in favor of the signals4 99 99 99 ,of course ,i remained in the background1 except1 as to giving explanations4 ,after a while ,cassatt1 ,pitcairn and ,thomson got into a discussion of the battery and other points1 and called me into the ring to enter into the discussion1 and it was quite animated for some time4 ,pitcairn proceeded to give his idea of what a signal should be1 and ,mr4 ,baldwin and the rest proceeded to show him that this1 was exactly his ideal4 ,mr4 ,gardner1 after learning modus operandi from diagrams c4 proceeded to lay down the law to the rest1 demonstrating how they would have 'prevented those accidents4' ,they were all very much pleased with the signals but their operation seemed such a surprise that ,i judge it will take them several days to think over and realize the actual operation and importance of the thing4 ,robinson's ,work in ,new ,england ,in ,december1 #ahge1 ,mr4 ,robinson went to ,boston and took up his residence there4 ,in ,january1 #ahgf1 he made an installation of his closed rail circuit system between ,elm street and ,north avenue1 ,west ,somerville1 on a branch of the ,boston and ,lowell railroad4 ,this installation worked perfectly from the beginning4 ,the ,emperor of ,brazil ,examines the ,robinson ,signal ,system ,in ,june1 #ahgf1 ,his ,imperial ,majesty1 ,dom ,pedro ,,ii1 ,emperor of ,brazil1 being then in ,boston1 graciously accepted an invitation from ,mr4 ,robinson to examine his ,wireless ,signal ,system in operation on the ,boston ,lowell railroad4 ,accordingly1 on ,june #ad1 they proceeded together by special train to ,west ,somerville for the purpose4 ,the following is an account of the visit1 from the ,boston ,post of ,june #ae1 #ahgf3 ,,dom ,,pedro ,,ii4 ,,his ,,majesty ,,witnesses ,,the ,,operations ,,of ,,railroad ,,signals4 ,though the visit of ,his ,majesty1 the ,emperor of ,brazil1 to this city has been a brief one1 yet it is not hazardous to say that no other crowned head or representative of royalty who has ever appeared in ,boston has more closely inspected the places where centre arts1 sciences and manufacturers than he4 ,in compliance with an invitation1 the ,dom proceeded yesterday morning to witness the workings of ,robinson's ,wireless ,signal ,system1 now in operation on a portion of the ,lowell railroad4 ,the ,emperor and several members of his suit took passage on board a special train on the ,lowell railroad soon after #h o'clock yesterday morning and arrived at the ,west ,somerville station about #h3cj1 where they were met by ,professor ,robinson1 who at once began to explain to the royal party his system4 ,at ,elm street a large visual signal is placed which is controlled by the current from a single cell of a battery connected with the rail sections at ,north avenue1 no line wires whatever being used4 ,while the ,emperor watched the signal at ,elm street trains were run over the whole length of the signal section in both directions4 ,as soon as the train entered upon the section at either end1 the signal1 without a moment's delay1 showed the track blocked1 and when the train passed off the section it instantly changed the signal to all clear4 ,then a rail was torn up1 and almost instantly thereafter the signal denoted danger and remained so until the rail was restored and properly coupled up1 when it as quickly changed to all right4 ,mr4 ,robinson gave various other demonstrations illustrating the working of the system4 ,to all the tests the signal instantly responded4 ,his ,majesty was much interested1 and entered into a somewhat lengthy discussion with ,professor ,robinson in regard to the operations which he had witnessed4 ,the ,emperor's questions displayed profound scientific knowledge1 and he fully comprehended the system4 ,at the conclusion of the experiment ,dom ,pedro thanked ,professor ,robinson for his kindness in explaining and illustrating his system1 and invited him to communicate with the ,brazilian government with a view to introducing the system in ,brazil4 ,on the return of the party to the ,lowell depot in ,boston1 the ,emperor was received with great applause1 which he politely acknowledged by waving his hat4 ,it will be interesting to note that on ,june #ad1 #ahgf1 the day the ,emperor inspected the ,robinson ,signal ,system at ,west ,somerville1 the battery had been in operation exactly #ahj days without any attention whatever except that on two occasions a little water had been added to make up for evaporation1 the signal working perfectly all that time and the battery with full strength4 ,illustration3 ,fig4 #d4 ,robinson's ,electro-,mechanical ,signal in ,operation at ,west ,somerville when ,inspected by the ,emperor of ,brazil in #ahgf4 ,the following is from a report on the above signal by the station agent at ,elm street1 dated ,june #b1 #ahgg1 eighteen months after it had been installed3 ,robinson's ,electric ,signal at this place has been working uninterruptedly since it was first put in operation4 99 99 99 ,the signal is entirely reliable4 ,the above signal continued to work perfectly for a number of years until the signal post1 which was of wood1 rotted down4 ,illustration3 ,fig4 #d;a4 ,the signal mechanism used on the ,robinson signal at ,elm street was of the electro-mechanical type4 ,figure #d is a half tone of the identical signal mechanism in operation there when the ,emperor of ,brazil examined the system with ,mr4 ,robinson1 on ,june #ad1 #ahgf4 ,it is pointed out that the above signal mechanism1 ,fig4 #d1 shows a battery or pole changing attachment which is more clearly shown in ,fig4 #d;a1 reproduced from ,robinson's ,british patent ,no4 #cdgi of ,august #bi1 #ahgi4 ,in this device the movement of the cam i#b not only changes the battery but changes the polarity through the magnet ,m#b1 which may be placed anywhere and used for any purpose4 ,a special device for the same purpose was used not only in connection with the relay on the ,west ,somerville signal1 but on many others installed by ,mr4 ,robinson4 ,this battery and pole changing device is more fully described in ,robinson's ,u4,s4 patent1 ,august #be1 #ahgd1 ,no4 #aed1ebj1 ,automatic ,commutator2 ,application filed ,july #ah1 #ahgc4 ,the following extract therefrom1 and claim1 may be interesting3 ,it will be observed also1 that while the actual change of battery may be caused to take place when the magnet attracts its armature1 yet ,i prefer to arrange it so that no change of connections shall take place when the armature is attracted1 the actual change taking place only during the reverse movement of the armature1 caused by the retractile force of the spring4 ,furthermore1 when desired1 the batteries may be so connected in circuit that reverse currents shall be passed through the magnets every time the batteries are changed4 ,,claim #b4 ,in combination with the electro-magnetic commutator having the described circuit connections1 the rail sections ,a',a991 the one closing the circuit through the commutator1 and thereby determining the battery to be connected to the other rail section1 substantially as and for the purpose set forth4 ,it must be admitted that there does not seem to be a very long step between the disclosures of this patent and the present method of operating a distant signal by reversing current through a rail section4 ,it will be observed that in this patent one rail is used as a return for a plurality of batteries connected to independent opposite rail sections4 ,in an autograph letter addressed to the author by ,professor ,henry1 secretary of the ,smithsonian ,institution1 under date of ,october #ad1 #ahge1 the ,professor discusses ,robinson's peculiar method of using batteries in signaling by which he obtained the above wonderful durability of #ahj days or more without renewal1 and pronounced the results obtained very remarkable4 ,his discussion of the subject is somewhat suggestive of the principles of the storage battery4 ,switches ,in #ahgf1 #g and #h1 ,mr4 ,robinson made a number of installations on the ,boston and ,providence1 ,old ,colony and the ,boston1 ,lowell and ,nashua railroads4 ,on the latter road1 at ,wilmington ,junction1 he equipped two parallel sections of the double track1 including six switches1 in this short space1 five of them connected with one of the blocks4 ,these sections were arranged as regular closed circuit blocks1 operative under the moving trains4 ,the switches were also connected up in such a way that every switch had to be closed and locked for the main line or the danger signal would be exposed against approaching trains4 ,this installation was made in #ahgf4 ,the switch connection applied to these switches is shown in ,fig4 #e and a general plan of the same is illustrated in ,fig4 #f4 ,both of these figures are reproductions from ,robinson's aforesaid ,british patent of #ahgi4 ,illustration3 ,fig4 #e4 ,illustration3 ,fig4 #f4 ,it will be observed that when the switch is on the main line the wires #g1 #h are connected by the plug #f on the switch connection1 thus completing a working circuit through the rails and around the switch1 but when the switch is placed for a siding the wires #g and #i are connected by the plug #e1 thus short circuiting the current from the magnet ,m1 thus producing the same effect as would the presence of a train on the section4 ,it is always better to short circuit the current than trust to the mere opening of circuit since short circuiting is sure to produce instantaneous results4 ,it will be observed1 however1 that in the above case the movement of the switch connection both opens the rail circuit and short circuits the current from the relay4 ,it may be here stated that ,mr4 ,robinson equipped three switches in one closed circuit block1 in the manner described above1 on the ,philadelphia and ,erie railroad in #ahgc4 ,illustration3 ,fig4 #g4 ,fig4 #g1 from ,robinson's ,english patent of #ahgi1 aforesaid1 shows the switch ,g arranged to operate the signal by hand from an office1 station or telegraph post by the roadside1 as heretofore described4 ,drawbridges ,about the time he made the ,wilmington installations above described1 ,mr4 ,robinson made an installation of his system also on the ,old ,colony railroad1 in which one block signal section at ,somerset included a drawbridge4 ,he included the track rails of the drawbridge in the track circuit in such a way that the withdrawing or loosening of any one of the bridge lock-bolts would display the danger signal1 which remained exposed until the bridge and its lock-bolts were all restored to their normal condition insuring safety4 ,tunnels ,long wet tunnels present peculiar difficulties to the reliable operation of the rail circuit2 and yet these difficulties are readily overcome by including one or more additional relays in the signal section1 as shown in ,fig4 #h1 which illustrates the application of the ,robinson track circuit system as applied to the ,tehauntepec tunnel in ,california4 ,mr4 ,robinson forwarded the signals and necessary instructions1 and the installation was made by ,mr4 ,stephen ,d4 ,field1 secretary of the ,electrical ,construction and ,maintenance ,co4 of ,san ,francisco4 ,illustration3 ,fig4 #h4 ,figure #h is from a sketch made by ,mr4 ,field in a letter dated ,san ,francisco1 ,march #ba1 #ahgg1 addressed to ,mr4 ,robinson4 ,in this letter ,mr4 ,field says3 ,i am just in the receipt of yours of the #abth4 ,i had anticipated your diagram and have the signals arranged as you show4 ,i use the system connected up as follows3 ,in the tunnel the rails are buried in wet mud2 outside no moisture touches them for six months of the year4 ,it will be noted that in the above case the signal section is two miles long1 the tunnel being one mile long1 with its rails buried in wet mud1 and the section extending one-half mile at either end of the tunnel4 ,an extra relay and battery are placed in the center of the section connected up as shown4 ,thus1 where conditions require1 a signal section may be divided up into a number of sub-sections4 ,later advices showed that the above signals worked perfectly and gave entire satisfaction4 ,insulated ,joints ,in #ahgb and the early seventies ,mr4 ,robinson insulated the rail joints to form the sections by wooden bars1 substantially as shown in ,fig4 #i4 ,illustration3 ,fig4 #i4 ,illustration3 ,fig4 #aj4 ,in #ahgf and later he usually insulated the joints as shown in ,fig4 #aj1 using the ,fisher ,norris trussed joint as a basis4 ,vulcanized fiber is placed between the bottom of the rail ends and the base plate1 and fiber is placed between the flanges of the rails and the forelocks1 and fiber1 the shape of the rail section is placed between the ends of the adjacent rails1 all as shown in ,fig4 #aj4 ,this makes an excellent insulated joint1 both mechanically and electrically4 ,rail ,bonding ,dry rust forming between the fish plates and the rails of the track1 at the joints1 makes a poor conductor1 and hence the low current1 from only one or two cells of battery used in the rail circuit for signaling is very liable to find sufficient resistance at the joints from this cause to prevent the continuous passage of the current through the rails to the relay4 ,mr4 ,robinson discovered this difficulty in his first experiments in rail signaling in #ahgb and the necessity for making a reliable electrical connection from rail to rail in order to insure the reliability of his closed circuit signal system4 ,as heretofore stated1 therefore1 he at that time conceived the invention of the bond wire1 ,fig4 #aa1 for this purpose1 the connection to be made by drilling holes in the adjacent rails1 driving the ends of the wires tightly into these holes1 and making the connection so close that there would be no room for moisture to penetrate or rust to form4 ,and as an alternative form he proposed to secure the ends of the wire1 or of a plate1 to the adjacent rails by soldering1 as shown in ,fig4 #ab4 ,in those early days there were serious technical objections to both of these methods4 ,first3 ,the difficulty and expense of boring holes in all the rails of the section and connecting them up1 and the difficulty of getting the railroad company to consent to such an innovation to test what at that time might be regarded as an experiment1 and ,second3 ,soldering seemed impracticable on account of the difficulty of heating up the rail quickly enough at the required point4 ,mr4 ,robinson1 therefore1 postponed the application of the bond wire until he could secure better facilities for applying and using it4 ,he1 meantime1 experimented along other lines1 however1 for the purpose of securing good electrical connection between adjacent rails without boring holes therein4 ,one of these methods was very successful4 ,it consisted in the use of elastic split springs having their ends resting on the flanges of the adjacent rails1 and held in place by small blocks secured to the ties4 ,the passing of a train depressing the rails slightly caused a slight frictional movement between the rails and the springs1 thus preserving good electrical contact4 ,in the ,west ,somerville installation1 near ,boston1 made in ,january1 #ahgf1 as heretofore described1 ,mr4 ,robinson used the bond wire shown in ,fig4 #aa4 ,in applying this1 holes were bored in the rails and the wire1 fitting the holes as closely as possible1 were forced in4 ,a semi-circular punch was then carefully used to set the metal up close around the wire4 ,there has been no better bond wire devised since then except in mechanical construction4 ,bonds of various designs have been made heavier1 and with heavier end plugs for mechanical connection to the rails4 ,these are good features as they render the bond less liable to breakage1 and1 as is well known1 for electric railroads they should be much heavier than required in signaling1 for the sake of conductivity4 ,a bond wire1 to get best results1 should be homogeneous1 made of a single piece of metal1 or if made of several pieces1 all the pieces should be welded1 or at least1 soldered together4 ,they should be of sufficient length to insure flexibility without disturbing the connection if the rails should move relatively to each other1 and the whole circumferential surface of the plug end1 or its equivalent1 when possible1 should be in the closest possible direct contact with the rail1 that is1 the bond plug should make connection with the rail as nearly as possible--homogeneous4 ,welding would be the ideal connection but it is not always practicable4 ,the reason for the above is obvious3 that there should be no room left between the bond and rail for rust to form4 ,it follows then that a bond held in position by an independent plug which renders it necessary for the current to pass from the bond to the intermediate plug and from that plug to the rail1 is not the best form of bond1 for the reason that it presents a double surface on which rust may form4 ,figures #aa and #ab show ,robinson's bond wires and strips of #ahgb1 ,fig4 #ab showing the bond soldered to the rail4 ,in #ahgf1 #g and #h he used on various roads in the vicinity of ,boston1 the bond shown in ,fig4 #aa4 ,in #ahgf he used on the ,boston and ,providence road the bond shown in ,figs4 #aa1 #ac and #ad4 ,in the form shown in ,fig4 #ac1 holes are bored through the upper ends of the plugs1 which were slightly tapering4 ,the wire was forced through these holes1 and the wire and plugs were then soldered together with hard solder4 ,the plugs being materially larger than the wire1 could readily be driven home with a good deal of force1 thus insuring an excellent electrical connection without endangering the wire4 ,illustration3 ,fig4 #aa4 ,illustration3 ,fig4 #ab4 ,illustration3 ,fig4 #ac4 ,illustration3 ,fig4 #ad4 ,illustration3 ,fig4 #ae4 ,illustration3 ,fig4 #af4 ,in ,robinson's ,british patent ,no4 #cdgi1 of ,august #bi1 #ahgi1 aforesaid1 he illustrated the form of bond shown in ,figs4 #ae and #af1 which is an equivalent of that shown in ,fig4 #ad1 used by him in #ahgf4 ,mr4 ,robinson claimed the bond wire broadly in this ,british patent1 in the following claims3 #aj4 ,the wire ,a#c in combination with the rails ,b#c1 ,b#c1 and securely fastened thereto1 for the purpose described4 #aa4 ,in combination the wire ,a#c1 the rails ,b#c1 ,b#c1 and the rivets a#c1 a#c1 the whole arranged substantially as described for the purpose of securing electrical continuity between said rails4 ,the above is believed to be the first disclosure of means for electrically connecting rails by a bond wire in any patent1 although ,robinson had disclosed it to various parties1 and used it on installations years before4 ,on the subject of rail bonding the following bit of evidence may be of interest3 ,in a letter dated ,baltimore1 ,october #bi1 #ahgd1 addressed to ,mr4 ,robinson by ,mr4 ,j4 ,h4 ,c4 ,watts1 of ,watts ,co41 manufacturers of ,robinson's signal apparatus1 he says3 ,am afraid your idea of soldering a strip of copper to the rails will prove very troublesome in carrying out1 as it is a most difficult matter to heat so large a body of iron sufficiently to make a sure joint such as you require1 or that will stand the jarring of passing trains1 c41 to say nothing of sneak thieves who abound wherever copper is lying around loose4 ,i know however you scoff at theory so will 'dry up4' ,the electric dynamo of today has removed the above pointed out difficulty4 ,bond wires or strips are now welded to the adjacent rails for the purpose of securing reliable electrical connection between them4 ,welding is soldering1 according to the definition of the term4 ,thus1 the ,encyclopedic dictionary gives the definition3 ,solder3 ,to unite or cement together in any way4 99 99 99 ,in autogenous soldering the two pieces are directly united by the partial fusion of their contiguous surfaces4 ,thus1 more than thirty years ago ,robinson proposed to solder bond wires or strips to the rails for the purpose of securing good electrical continuity between the same4 ,but it became necessary to wait some twenty years for the development of a commercially practical process for accomplishing this result4 ,this is found in the modern electric welding process4 ,robinson's object was to secure a perfectly homogeneous joint or connection between the bond and the rail4 ,his invention1 in this connection1 consisted in a metallic bond arranged for electrically connecting adjacent rails of the track and means for forming a homogeneous connection between the bond and the rails4 ,this embraces any mode of accomplishing that result4 ,robinson had simply anticipated the electric process by some twenty years1 but that process now accomplishes the result in a simple manner impossible thirty years ago4 ,the splice bars now welded to opposite sides of street rails in many places are used primarily for the purpose of electrically bonding the rails2 incidentally they serve the double purpose of also making a good joint mechanically4 ,every electric railroad uses the bond wire or plate in some form1 originally invented and used by ,robinson1 for electrically bonding rails together4 ,thus1 it is clear1 this simple invention of ,robinson made more than thirty years ago1 an outgrowth of his original creation of the closed rail circuit system1 has made possible the electric railroading of today1 and the method of rail-bonding is now used on every electric railway using a rail return1 throughout the world4 ,illustration3 ,,robinson',s ,,latest ,,electric ,,signaling ,,apparatus4 ,fig4 #ag4 ,rings a ,bell on the ,engine when ,track ahead is all ,clear4 ,figure #ag is a reproduction from a postal card dated ,september1 #ahge1 and issued at that time4 ,it illustrates means for operating a positive safety signal in the cab of a locomotive when the track ahead is clear and safe1 the operative current passing through the rails from the distant end of the track section upon which the train is entering4 ,this system is elaborated in ,robinson's ,british patent of ,august #bi1 #ahgi1 where it is shown operatively applied to a single track in such a manner as to operate a signal on a locomotive approaching from either direction1 the operative current coming from the opposite end of the section--no line wires being used4 ,it is not thought necessary1 therefore1 to more fully describe the system here4 ,in ,general ,the scriptural injunction1 ,prove all things1 hold fast that which is good1 is the key note of scientific progress4 ,he who would discover truth must not accept anything because it is popularly accepted1 or reject anything because it is popularly rejected2 nor must he regard anything as impossible because never heretofore accomplished1 although perhaps attempted by the most able scientists4 ,while giving full weight to principles and laws demonstrated and verified by original investigations1 he must bear in mind that those principles and laws may be capable of various combinations and interpretations2 that the popular interpretation may not be capable of general application1 and if not1 it must be erroneous4 ,in short1 he must enter upon his investigations systematically1 independently and untrammeled by prejudice4 ,these remarks apply to electrical science with great force at the present time4 ,those who enter this field to advantage should be men of culture1 of theoretical knowledge1 and eminently practical4 ,these facts are illustrated by the efforts heretofore put forth in ,europe and the ,united ,states to develop systems of rail signaling4 ,such efforts1 in the early days1 appear to have been exerted principally by theorists whose propositions and complications prove them to be not only ignorant of some of the fundamental principles of electrical science1 but also1 some of them1 extremely unpractical4 ,that the efforts in this direction may be fairly understood we will direct attention to a few of the systems of rail signaling proposed1--those which have elicited most attention--giving outline illustrations of some of the circuits which form their bases1 and pointing out their defects and merits4 ,early ,rail ,systems ,so far as we have knowledge1 the idea of using the rails as conductors for electric signaling purposes was first suggested in an ,english patent of #ahdh4 ,this was merely a suggestion1 however1 and no attempt was made to describe any specific method of using the rails for the purpose4 ,in #ahec1 however1 an ,english patent was granted to ,george ,dugmore and ,george ,millward1 in which is described a method proposed for using the rails as conductors4 ,the design of the invention is to communicate between trains on the same line1 and between trains and stations1 for which purpose it is proposed to use long sections of rails4 ,the unpractical part of this system is that to make it operate it is necessary1 as the inventors say1 to insulate the opposite wheels of all the carriages from each other1 in order that electrical connection may not be established between the opposite rail line by the wheels and axle4 ,imagine one of our gigantic locomotives having its opposite drivers electrically insulated from one another6 ,figure #ah represents the signal system described in ,william ,bull's ,english patent of ,october #ca1 #ahfj4 ,in this system1 it will be observed1 the rail sections used are short1 twenty feet1 more or less1 and are the terminals of line wires which connect with the battery and magnet at the station4 ,the signal at the station is visual and consists of an indicator operated by wheel work actuated or controlled by the electro-magnet ,m shown in the diagram4 ,the signal as described1 moved in one direction only1 by a step-by-step movement4 ,in the following diagram ,m represents magnet and ,b battery4 ,illustration3 ,fig4 #ah4 ,william ,bull's ,british ,patent1 ,october #ca1 #ahfj1 and ,frank ,l4 ,pope's ,experiment at ,charlestown1 ,mass41 in #ahga4 ,mr4 ,bull says3 ,at the stations at which it is required that the progress of the train shall be indicated1 a battery is fixed and in connection therewith a dial or indicator1 both of which are also connected with the line permanent way wire1 the terminals of which are the pairs of insulated rails1 as before described4 99 99 99 99 99 ,when the train arrives at the contact points on the line1 the electric circuit would be completed by the wheels of the engine connecting the two insulated rails1 when the current would flow and actuate the electro-magnetic armature1 c4 ,the mode of insulating the rails from each other is described by ,bull as follows3--,between the end of the rails1 and also between the joint plates and rail ends1 ,i insert a thin piece of leather1 mill-board1 gutta percha1 or other suitable substance1 suitable for cutting off metallic contact1 and thereby insulate one rail of twenty feet1 more or less1 as may be necessary4 ,in ,pope1 in a description of his experiment at ,charlestown1 in a paper read by him before the ,new ,york ,society of ,practical ,engineers--of which1 by the way1 ,mr4 ,robinson was a charter member--and subsequently published1 admits that he did not use the rail circuit at all in any proper sense of the term4 ,on the contrary1 he used line wires forming his main circuit terminating in short sections of rails1 forty-two feet in length according to my recollection1 that is1 the length of one rail4 ,the train passing over the short rail section at one point closed the circuit through the line wires1 thus exposing the signal1 which was held in place by a detent4 ,the train1 having reached a distant point1 passed over another similar short section of rails1 closing circuit through another magnet which released the detent and reversed the signal4 ,it will be observed that the essential features of the device used in ,pope's experiment1 on which he laid great stress1 and described in ,bull's patent1 are identical1 that is1 the circuit closer consists1 in the one case of a section of rails twenty feet long1 more or less1 on open circuit1 and the other identically the same1 but with a rail section forty-two feet long1 both using line wires4 ,pope and his friends heralded this experiment--a revival of ,bull's device--as demonstrating a wonderful invention on the part of ,pope4 ,what ,robinson ,has ,done in ,automatic ,electric ,signaling #a4 ,he has created an epoch making invention of incalculable value to the human race in the wholesale saving of life and property on railroads1 an invention of increasing importance and efficiency as time passes and its use is extended4 ,it is an invention so unique and profoundly philosophical that those best skilled in the electrical art at the time it was made1 declared that it was contrary to all known laws of electrical action and could not possibly work4 #b4 ,robinson's invention was not an improvement on something that preceded it4 ,it had no precedent4 ,it was an entirely new creation involving principles and methods of operation never before known or used by anybody4 #c4 ,his invention was almost unique in this3 ,it was a basic invention conceived1 tested1 put in practical operation in many installations1 and perfected1 as a system1 in all its details1 by its original inventor4 ,he reduced it to its lowest terms and its highest efficiency1 a perfection and efficiency of operation which have not been exceeded since it left his hands many years ago4 #d4 ,his invention has made possible1 with safety1 the high speed railroading of today4 #e4 ,as already stated1 the automatic signal system used in and controlling the operation of traffic of the ,new ,york subway is purely and exclusively a ,robinson system4 #f4 ,robinson's automatic signal system has increased the traffic capacity of the ,new ,york subway at least three-fold1 and probably twice that4 ,without it the subway equipment could not transport with safety1 one-fourth the number of passengers now carried4 #g4 ,this invention has created a practically new industry1 giving employment to many thousands of men1 in various capacities1 skilled and unskilled4 #h4 ,it is enriching the railroads by enabling them to carry on twice the traffic1 with a given equipment1 that they could ever do before1 and also by saving their equipment from destruction by collisions and other destructive means4 #i4 ,the ,robinson automatic system is admittedly the only signal system ever produced that meets all the requirements of safe and rapid railroading4 #aj4 ,robinson's subsidiary invention of the rail bond1 made more than fifty years ago in connection with his automatic system of signaling1 and now in universal use on all electric roads using the track return1 throughout the world1 has made possible electric railroading as practiced today4 ,without this ,robinson bond or its equivalent those electric roads using the track return could not be operated4 #aa4 ,the ,robinson automatic system is a humanitarian invention of the very highest order1 to which thousands of travelers by rail are indebted for the preservation of life and limb4 ,illustration3 ,w4 ,,robinson4 ,improvement in ,electric ,signaling ,apparatus for ,railroads4 ,no4 #acj1ffa4 ,patented ,aug #bj1 #ahgb4 ,,united ,,states ,,patent ,,office ,,william ,,robinson1 ,,of ,,brooklyn1 ,,new ,,york4 ,improvement in ,electric-,signaling ,apparatus for ,railroads ,specifications forming part of ,letters ,patent ,no4 #acj1ffa1 dated ,august #bj1 #ahgb4 ,be it known that ,i1 ,,william ,,robinson1 of ,brooklyn1 in the county of ,kings and ,state of ,new ,york1 have invented a new and useful ,electric ,signaling ,apparatus for ,railways1 of which the following is a full1 clear1 and exact description1 reference being had to the accompanying drawing forming part of this specification4 ,the figure represents a top view of a double-track railway1 with suitable sections and wire connections1 together with an elevation of the signal-box with its face removed to show the signal within1 the whole being arranged to illustrate my invention4 ,the object of this invention is to operate electric signals1 audible or visible1 by means of moving or standing vehicles or trains without the use of ordinary track connections for closing or breaking circuits1 and without the use or with a limited use of line-wires for conducting the electric current1 the rails of the track being used for the latter purpose4 ,the invention consists in an improved signal of very simple construction1 by which great ease of action is secured4 ,it also embraces certain peculiarities in the arrangement of wires from the signal and battery to the track4 ,a in the drawing represents a double-track railroad4 ,c is a section of track1 which may be a mile long1 more or less1 and having its rails a b separated from metallic contact with the rails of the sections ,d and ,e1 as shown at a' b'4 ,in like manner the section ,c' of the other track has its rails separated from metallic contact with the rails of the sections ,d' and ,e'4 ,the rails a b c d should each have metallic continuity throughout the length of its section4 ,the signal-box ,f is constructed of any suitable material1 and is provided with an orifice1 preferably in the center1 covered with glass windows capable of illumination1 through which the signal may be seen when exposed1 day or night4 ,within this signal-box is placed the signal ,g1 consisting of a disk1 ,s1 attached to the lever e1 which1 pivoted at f1 turns on a horizontal axis4 ,to the lever e or its arbor is fixed the small projection or lever1 preferably segmental1 g4 ,a cord1 link1 chain1 or delicate elastic spring1 i1 is attached to the lever g and to the upper part of the long lever ,l1 in such a manner that when the armature m1 which is attached to the lever ,l1 is attracted by its magnet ,m and the upper part of said lever ,l swings in the direction of the arrow z1 the upper part of the segmental lever g moves forward and downward1 thus permitting the chain i to work closer to the pivot f4 ,by this arrangement it will be seen that the greatest leverage-power is secured for moving the signal when the armature m is the greatest distance from its magnet and the magnetic force is consequently weakest1 the leverage-power diminishing gradually as the armature approaches the magnet4 ,the vertical lever ,l moves on a horizontal axis1 f'1 and is prevented from swinging too far back from the magnet by the adjustable stop s1 which may be so adjusted as to bring the armature m a greater or less distance from its magnet ,m1 as may be found necessary4 ,the levers ,l and e may be made of any suitable material and in any manner2 but are preferably constructed of thin tubular metal for the purpose of securing great strength and rigidity with minimum weight and friction of parts4 ,furthermore1 the disk ,s is counterbalanced by an adjustable weight1 w1 and by making that part of the lever e embraced between the pivot f and the disk ,s of considerable length1 the disk ,s is brought from a state of concealment to a state of exposure1 or the reverse1 by passing through a comparatively small angle1 and by arranging the disk-lever e1 as shown in the drawing1 in such a manner that in bringing the disk from a state of concealment to a state of exposure1 or the reverse1 said lever e shall swing to and beyond a horizontal position1 the greatest uniformity of motion with the least possible loss of power are secured4 ,having thus described the construction of the visual signal ,g1 it will be seen that when the electro-magnet ,m is charged it attracts the armature m to itself1 thus swinging the upper end of the lever ,l in the direction of the arrow z1 and carrying the upper end of the lever g forward1 at the same time turning the same together with the lever e on the axis f1 and carrying the disk ,s down into the position indicated in dotted outline4 ,now connect one pole of the battery ,b with the rails a and c1 and the other pole with the rails b and d of the sections ,c and ,c' by means of the wires k and k'1 respectively4 ,in like manner connect the ends of the coils of the magnet ,m1 the one end with the rails a and c and the other end with the rails b and d of the same sections ,c and ,c' by the wires l and l'1 as shown in the drawing1 and the apparatus is operative4 ,the wires from the battery and the signal to the track are preferably insulated4 ,before describing the operation of the apparatus as a whole1 it may be stated that the electric current will follow a naked metallic conductor if of sufficient surface1 even when immersed in a river or in the mud at the bottom of a river1 because the metal offers less resistance to its passage than either water or mud4 ,much more will it follow the rails of a railroad track when they are made a part of the circuit1 since the rails present a large surface of good conducting material1 which offers much less resistance to its passage than any surrounding mediums2 and it is well known that when several courses are presented the electric current will follow that course which offers least resistance to its passage4 ,the mode of operation is as follows3 ,suppose the sections ,c and ,c' to be entirely clear of cars2 then the electric current from the positive pole ,p of the battery ,b will pass as indicated by the arrows x x1 through the wire k'1 rail b1 wire l'1 and magnet ,m1 charging the same1 and return through the wire l1 rail a1 and wire k1 as indicated by the arrows y' y1 to the negative pole ,n of the battery4 ,the magnet ,m1 being thus charged1 attracts its armature and swings the signal-disk ,s into the position of concealment shown in dotted outline1 and holds it in that position as long as the sections ,c ,c' are clear4 ,now let a train enter upon ,c or ,c'1 as indicated at ,h ,c'1 and the wheels and axles of the same will bridge over the rails c and d1 and thus1 by offering a large conducting-surface1 will present to the electric current a complete circuit1 which offers much less resistance to its passage than that through the magnet ,m4 ,the electricity now takes the course over the wire k'1 rail d1 wheels and axle ,h1 returning1 by the rail c and wire k1 to the battery1 as indicated by the arrows x x' y1 using the rails c and d1 as will be seen1 with their bridge1 and entirely avoiding the magnet ,m1 which1 being thus demagnetized1 lets go its armature1 and the counterpoise w1 which slightly overbalances the disk ,s1 carries the same up in front of the orifice1 into a position of exposure1 where it remains1 as shown1 while a train is on section ,c or ,c'4 ,when1 however1 the train has run off1 leaving sections ,c and ,c' clear1 the magnet ,m is instantly charged again and the signal-disk is removed and kept concealed until the track is again blocked by the presence of another train1 when the same process is repeated4 ,when the signal-disk is in a position of exposure1 as shown1 the lever l may serve to close an additional circuit through the battery ,b1 which may be used to operate an alarm1 ,i1 in conjunction with the signal ,s1 or to actuate another signal at a distant point4 ,furthermore1 the concealment of the signal ,s may serve to close another circuit for exposing another signal1 or the reverse4 ,instead of using the signal ,g1 constructed as herein minutely described1 a signal of any suitable construction may be used without affecting the spirit of the invention4 ,furthermore1 instead of using the magnet ,m to actuate the signal directly1 it may be used as a relay1 operating1 when charged1 to keep the circuit which directly actuates the signal open or closed1 as desired4 ,it is evident that an alarm may be used either in conjunction with or independently of a visual signal4 ,the drawing shows an application particularly adapted to road-crossing signals on a double track4 ,the signals may be used1 also1 on a single track and be applied as block signals and for other purposes on single or double tracks4 ,when used as a block-signal or for other purposes1 it may be desirable to indicate at a distant station when the signal is operative4 ,to accomplish this object1 carry one of the wires from the magnet ,m to the distant station4 ,here let the wire be passed through the coils of a bell-magnet or other signaling device1 and thence be carried to the track and attached to the same1 as already described4 ,the office signal will operate simultaneously with the signal ,s4 ,thus any desired number of signals may be operated simultaneously1 at different points1 from a single section of track4 ,by a slight modification of the plan described an efficient switch and drawbridge signal may be operated1 the rails being used as conductors4 ,thus half a mile1 more or less1 from a switch may be placed a signal-box and signal1 substantially as described1 and connected with the rails1 as shown4 ,near this point let the rails be divided1 taking care that the signal and battery wire are connected to the section toward the switch4 ,now1 while the switch is on the main line1 the bars connecting the rails of the switch will act as a bridge to divert the electricity from the signal-magnet4 ,but when the switch is misplaced the metallic connection of the rails of the track will be interrupted4 ,the signal-magnet will thus become charged and the position of the signal changed4 ,in this case the signal should be exposed when the magnet ,m is charged4 ,in like manner a cross-bar may bridge the rails on a draw-bridge4 ,the displacing of the draw-bridge or withdrawing of the bolt or bolts which hold the same in position will allow the signal-magnet to become charged and the signal to be changed1 substantially as described1 in connection with a switch4 ,it is not necessary in all cases that the rails a and b1 section ,c1 should both be separated from metallic contact with the sections ,d and ,e4 ,it may often1 if not always1 be sufficient to separate only one of said rails from such metallic contact with the adjacent sections4 ,what ,i here claim as new1 and desire to secure by ,letters ,patent1 is-- #a4 ,the battery ,b and magnet ,m1 so connected with the rails of a section of railroad track that when said section is bridged by the wheels and axle of a car the electric circuit is changed and the signal operated through the demagnetization of the magnet ,m1 substantially as specified4 #b4 ,a signal constructed partially of tubular material1 for the purpose of securing lightness combined with strength1 in the manner substantially as herein set forth4 #c4 ,the arrangement of the pivotal bearing of the lever e at a point midway between the horizontal lines of exposure and concealment of the signal-disk1 as shown and described1 for the purpose set forth4 #d4 ,the combination of the elastic spring i1 or its equivalent1 with the levers ,l and e and signal-disk ,s1 substantially as set forth4 #e4 ,the battery ,b1 in combination with the wires k k'1 rails a b of a railroad track1 wires l l'1 and magnet ,m1 substantially as and for the purpose herein described4 #f4 ,the additional or local circuit r1 in combination with the magnet ,m1 wires l l' k k'1 battery ,b1 and section of rails of a railroad track1 for operation1 essentially as described4 ,,william ,,robinson4 ,witnesses3 ,,john ,,rooney1 ,,van ,,wyck ,,foster4 ,,dr4 ,,william ,,robinson#b ,electrical and ,mechanical ,engineer ,fellow ,american ,institute of ,electrical ,engineers ,graduate of ,wesleyan ,university with ,degrees of ,a4,b4 and ,a4,m4 ,post ,graduate of ,boston ,university with ,degree of ,ph4,d4 #b ,reprinted from a circular published by ,dr4 ,robinson in #aiac4 ,data ,notes ,originator and patentee 7basic patents1 #ahgb7 of the ,closed ,track ,circuit ,system of ,automatic ,electric ,signaling1 the basis of practically every automatic electric block signal system in use on railroads today4 ,the following brief description and comments on this ,robinson closed track circuit system are from the ,third ,annual ,report of the ,block ,signal and ,train ,control ,board to the ,interstate ,commerce ,commission1 dated ,november #bb1 #aiaj1 pages #agg et seq4 ,the ,track ,circuit ,perhaps no single invention in the history of the development of railway transportation has contributed more toward safety and despatch in that field than the track circuit4 ,by this invention1 simple in itself1 the foundation was obtained for the development of practically every one of the intricate systems of railway block signaling in use today wherein the train is1 under all conditions1 continuously active in maintaining its own protection4 ,in other words the track circuit is today the only medium recognized as fundamentally safe by experts in railway signaling whereby a train or any part thereof may retain continuous and direct control of a block signal while occupying any portion of the track guarded by the signal4 ,invention of the ,rail ,circuit ,to ,mr4 ,william ,robinson the ,patent ,office records concede the honor of having devised the first practical track or 'rail circuit4' ,this comprised what is termed the closed track circuit in distinction from the open form that preceded it4 99 99 99 ,closed track circuits are very reliable1 wholly safe in principle1 and simple of application and maintenance4 99 99 99 ,attention is therefore directed to the closed track circuit--the basis of all modern automatic signal systems that are entitled to recognition as embodying the highest attainments in the matter of safety4 ,the ,closed ,track ,circuit ,the closed track circuit in its simplest form consists of the two rails of a section acting as prime conductors1 a generator maintaining a difference of potential between them when the rails are unoccupied1 and one or more relays connected across the rails4 99 99 99 ,the closed track circuit maintains the relay1 normally1 in an energized state1 and the influence of the train upon the rails is to totally de-energize it by shunting or short-circuiting the generator--a thing as effectively done by a single car or locomotive as by a train of any length1 for all practical purposes4 99 99 99 ,a failure of the generator or a break in the circuit1 whether in the rails themselves or in other parts of the circuit1 produces the same effect upon the relay as that of a train upon the rails4 ,this is in full conformity with the accepted principles of safe signaling1 which give heed not alone to the action of the devices of the system under normal conditions1 but embrace also an equal regard for safe results following derangements of them4 ,historical ,notes ,in this connection a few historical notes on the origin and introduction of the closed rail circuit system of automatic electric block signaling on railroads may prove of interest4 ,in #ahgj ,mr4 ,william ,robinson exhibited at the ,american ,institute ,fair held in ,new ,york ,city1 an elaborate working model of an automatic electric signal system for railroads4 ,this was a road crossing signal operated by trains approaching in either direction4 ,when at a suitable distance the train set a gong ringing at the road crossing ahead1 which continued sounding an alarm until the train had passed1 when it ceased ringing4 ,in this model the relays were de-energized by short circuiting1 although the signal was operated on the normally open circuit plan4 ,this is believed to be the first case in which short-circuiting had been used in the operation of railway signals4 ,in #ahga ,mr4 ,robinson installed this system as an automatic block signal on a block over a mile in length1 at ,kinzua1 ,pa41 on the ,philadelphia and ,erie ,railroad4 ,this installation embodied a relay1 a large visual signal under control of the relay1 a heavy electric gong operated in conjunction with the visual signal1 all at the signal station4 ,from this station an overlap extended to the agent's station a mile ahead4 ,here a signal bell was provided so that when the visual signal was actually in the danger position it closed circuit on the bell magnet in the agent's station1 the hammer remaining against the bell until the reversal of the distant signal opened the circuit of this check signal4 ,this system worked perfectly1 performing all claimed for it2 but it was a normally open circuit system1 the only principle ever dreamed of up to that time for operating an automatic electric railway signal4 ,immediately on the completion of this open circuit installation ,mr4 ,robinson began to look for weak points about it1 and soon discovered several now well known as inherent in all normally open circuit systems1 not the least of which was that if the circuit were broken or the current failed from any cause the signal would remain at safety1 thus showing a false signal although danger might be imminent1 a radical error in principle fatal to the reliability of any normally open circuit system of signaling4 ,he therefore1 after much study1 devised the closed track circuit system1 the construction and operation of which are clearly described above by the ,interstate ,commerce ,commission4 ,in devising this system ,mr4 ,robinson reasoned that to make an efficient and reliable system every pair of wheels in the train must control the signal1 whereby a single car on the block1 or a break in any part of the circuit1 or loss of current from any cause affecting the relay1 would keep the signal at danger as effectively as the presence of a whole train on the block4 ,these considerations led him to the invention of the closed track circuit operating as heretofore clearly described by the ,interstate ,commerce ,commission4 ,before making tests of the system1 however1 he applied for and was allowed basic patents on the closed track circuit system in the ,united ,states and ,france1 the ,united ,states patent dated ,august #bj1 #ahgb1 ,no4 #acj1ffa1 and the ,french patent ,february #bi1 #ahgb1 ,no4 #id1cic4 ,having all the signal apparatus in operation at ,kinzua1 in the open circuit system1 as above described1 it was a simple matter for him to test the closed circuit system at this point4 ,he therefore divided the opposite rails of the track into sections insulated from the adjacent continuous track rails and connected the relay terminals to these sections at one end and similarly connected a battery thereto at a suitable distance from the relay1 thus forming a closed track circuit4 ,this being done1 the first train that passed connected the opposite rail lines through the wheels and axles1 short circuited the relay1 thus operating all the signal circuits under its control1 thereby practically demonstrating the feasibility of the system4 ,this was in #ahgb4 ,this block was extended to the agent's station over a mile from the signal1 at which station the track battery was placed and also a switch for the manual operation of the signal1 and also an overlapping telltale signal showing to the agent when the distant main signal was actually exposed at danger4 ,the signal also indicated to the agent the approach of a train when a mile away4 ,another installation was immediately ordered to be made at ,irvineton on the same road4 ,this was completed early in #ahgc and worked perfectly from the beginning1 performing all the functions described in connection with the installation at ,kinzua4 ,the locomotive engineers were greatly interested and soon christened the ,irvineton signal ,the ,old ,reliable4 ,this was followed by other installations on this road and in #ahgc ,mr4 ,robinson had made installations of his closed rail circuit system of signaling on four different railroads1 followed by various installations on many other railroads in the following years1 as he was the sole owner of the system for about nine years1 that is1 until about #ahhj or #ahha1 when the ,westinghouse people obtained control of the system by the purchase of ,robinson's interests4 ,this was promptly followed by a reorganization under the name of the ,union ,switch and ,signal ,company1 the terms ,union and ,signal representing the ,robinson interests in the reorganization4 ,this company thus became the sole owner of the ,robinson ,closed ,circuit ,system of signaling until the expiration of his patents1 when all other signal companies adopted the ,robinson system as the basis of their signal work4 ,the original name of the ,robinson ,company was ,the ,union ,electric ,signal ,company1 which ,robinson organized and owned in #ahgh4 ,in the reorganization the word ,electric was canceled from this title and the words ,switch and substituted1 thus forming the present title3 ,the ,union ,switch and ,signal ,company4 ,rail ,bonding ,experience at ,kinzua with a very poor track demonstrated the necessity of a rail bond to secure reliable electrical continuity throughout the rails constituting the block4 ,here1 in #ahgb1 ,mr4 ,robinson conceived the invention of the bond wire as used today4 ,in an effort1 however1 to avoid the handicap of having to bore two holes in every rail of long sections of track1 he equipped a signal section in #ahgc with elastic steel plates bearing on the adjacent rails at the joints4 ,this did not prove as satisfactory1 however1 as the bond wire4 ,he therefore used bond wires made after his original conception1 on every installation he made after #ahgc4 ,he made his bond wire in two forms4 ,in the second form he made studs slightly tapering1 bored holes through them1 inserted the ends of the wire in these holes1 brazed them together and drove these studs securely into holes bored in the adjacent rails4 ,an examination of these bonds after several years' service showed that they were apparently in as good condition mechanically and electrically as when first put in place4 ,the ,rail ,bond is now an essential basic feature of practically every one of the electric railway systems now in operation1 since they all use the track for a return1 and the track rails must be securely bonded in order to insure indispensable electrical continuity of the circuit4 ,in addition to his signal system1 therefore1 ,dr4 ,robinson is clearly entitled to the credit of having made1 before the inception of electric railroading1 a simple basic invention in his bond wire1 which has made modern electric railroading possible1 an invention indispensable to the successful operation of electric railroading as practiced today4 ,this invention has saved the electric roads untold millions of dollars and enabled them to accomplish results in a simple manner which could not otherwise be as well secured at any cost1 by the only alternative method1 of running return contact conductors in the air4 ,,william ,,robinson4 ,illustration3 ,,william ,,robinson1 ,,ph4,d42 ,e4 ,m4,e4 ,original inventor and patentee of the ,automatic ,electric ,signal ,systems now in use on the leading railroads in the ,united ,states and ,foreign ,countries4 ,,dr4 ,,robinson',s ,,record ,,from ,,wesleyan ,,university ,william ,robinson1 ,b4,a41 #ahfe2 ,m4,a41 #ahfh1 ,alpha ,delta ,phi4 ,ph4,d4 ,boston ,university1 #aijg4 ,born ,november #bb1 #ahdj1 in ,ireland4 ,principal of ,high ,school1 ,ansonia1 ,conn41 #ahfe-ff4 ,in the oil region1 ,pennsylvania1 #ahff4 ,taught in ,stamford1 ,conn41 #ahfg4 ,principal of ,spring ,valley ,academy1 ,n4,y41 #ahfg-fi4 ,engaged in the oil business in ,pennsylvania1 #ahfi-gb4 ,president and ,general ,manager of the ,robinson ,electric ,railway ,signal ,company1 #ahgc4 ,engaged in business in ,boston1 ,mass41 #ahge-ha4 ,organized the ,union ,electric ,signal ,company1 #ahgh4 ,traveled in ,europe1 ,egypt and ,palestine for fifteen months1 #ahgi-hj4 ,inventor of the ,robinson wireless electric railway signal system1 of the ,robinson radial car truck1 of the coaster brake used on bicycles1 of roller bearing skates1 and of a repeating telephone4 ,engaged in developing and practising electric engineering4 ,author3 ,history of ,automatic ,electric and ,electrically ,controlled ,fluid ,pressure ,signal ,systems for ,railroads4 ,died ,january #b1 #aiba1 ,brooklyn1 ,new ,york4 ,a4,i4,e4,e4 ,,record ,,of ,,dr4 ,,william ,,robinson ,copy of ,dr4 ,robinson's record made from original application ,no4 #abfe to the ,american ,institute of ,electrical ,engineers1 #cc ,west #cith ,street1 ,new ,york ,city4 7,record filed ,july1 #aiji47 ,references given by ,dr4 ,robinson3 ,william ,b4 ,potter4 ,e4 ,w4 ,rice1 ,jr4 ,theodore ,stebbins1 ,dallas1 ,texas4 ,frank ,j4 ,sprague1 #afe ,broadway4 ,prof4 ,chas4 ,a4 ,cross1 ,m4,i4,t4 ,prof4 ,elihu ,thomson4 ,goss ,bryce1 ,mech4 ,eng41 #gf ,william ,street4 ,george ,l4 ,fowler1 ,cons4 ,eng41 #ec ,broadway4 ,wm4 ,wallace ,white1 ,foreign ,patent ,solicitor and ,consul1 #cji ,broadway4 ,,william ,,robinson 7,a4,m41 ,,ph4,d47 ,,electrical ,,and ,,mechanical ,,engineer ,born ,november #bb1 #ahdj1 ,north of ,ireland1 of ,scotch-,irish descent on paternal side and ,english on maternal side4 ,,eligible ,,for ,,transfer3 ,under clauses 7a7 and 7c74 ,,education3 ,graduate of ,wesleyan ,university1 full ,academic course1 receiving the degrees of ,a4,b4 in #ahfe and ,a4,m4 in #ahfh4 ,post-,graduate of ,boston ,university in #aijg1 with degree of ,doctor of ,philosophy2 course including ,electrical and ,mechanical ,engineering4 ,,occupation ,,and ,,work ,,done3 ,engaged in developing and practising electrical engineering from prior to #ahgj up to the present time 7#aiji74 ,original inventor and patentee of the automatic electrical and electrically controlled fluid pressure signal systems for railroads now in universal use on the leading railroads in the ,united ,states and foreign countries1 wherever and by whomsoever installed1 throughout the world4 #ahgj4 ,received four ,united ,states patents on this system2 applications filed earlier4 #ahgj4 ,exhibited an elaborate working model of the system at the ,american ,institute in ,new ,york1 showing the automatic signal system in operation under control of passing cars4 #ahga-b4 ,original inventor and patentee of the closed track circuit system of signaling4 ,received basic ,united ,states and ,french patents covering same1 in #ahgb4 ,applications filed1 #ahga4 #ahgj-ga4 ,original inventor and patentee of the automatic electro-pneumatic signal systems for railroads in use for many years past4 ,received basic ,british patent covering this system in #ahga4 ,so far as ,i have been able to ascertain on careful investigation1 this patent appears to be the first ever issued anywhere on this subject4 ,the following brief historical excerpt is taken from a ,united ,states patent granted to me on ,october #bj1 #aijh1 ,no4 #ija1chc1 on an electric railway system4 ,this patent is one of a bunch of eight taken out by me on the same date1 on the same subject4 ,the excerpt relates to my work in signaling4 ,the block signal system herein disclosed is an embodiment of the ,robinson electro-pneumatic system now in extensive operation on the ,pennsylvania railroad and many other leading railroads in this and other countries1 embodying the closed circuit rail system for which a basic ,u4,s4 patent was granted to me on ,august #bj1 #ahgb1 ,no4 #acj1ffa 7reissued ,july #g1 #ahgd71 the electro-pneumatic signal system disclosed in my ,british patent of ,august #cj1 #ahga1 ,no4 #bbhj1 the subject matter of both of which patents is disclosed in my ,french patent of ,february #bi1 #ahgb1 ,no4 #id1cic4 ,the electro-pneumatic signal system disclosed in the above named patents is also disclosed in my ,united ,states patent dated ,november #g1 #ahhb1 ,no4 #bfg1bei4 ,as above indicated the block signal system herein described comprises the system described in my above named patents and now in general use on leading steam railroads1 but modified and improved in a way adapting it for reliable and efficient use in connection with electric railroads of the sectional third rail type4 ,the admission of the above brief history in the above described1 and substantially in two other patents of the same date1 is1 of course1 a complete verification of its historical accuracy by the ,patent ,office4 #ahgb4 ,in #ahgb ,i put the closed track circuit system of signaling in practical and successful operation at several points on different divisions of the ,philadelphia and ,erie railroad1 and on other roads4 #ahgb-gi4 ,in #ahgb to '#gi ,i installed the closed circuit rail system of automatic signaling on various railroads in ,pennsylvania1 ,new ,england and elsewhere4 ,i perfected the system and put it in as perfect and efficient and durable operation at that time as it is in today1 including all its functions of block1 switch1 road-crossing1 overlapping1 rear and front1 tell-tale and broken rail detector4 #ahgh4 ,organized and owned the ,union ,electric ,signal ,company1 based solely on my signal patents1 at that time nine in number4 ,some time afterwards ,george ,westinghouse and his associates bought the controlling interest in the ,union ,electric ,signal ,company and reorganized the company under the name of the ,union ,switch and ,signal ,company4 ,thus1 the automatic signal system of the ,union ,switch and ,signal ,co4 consists1 in every essential particular1 of the ,robinson system1 pure and simple4 ,it may be here pointed out that all the railway signal companies now in operation1 installing automatic signals under whatever name1 are using the ,robinson system bodily1 and have been since the expiration of ,robinson's basic patents4 ,there is no other system1 as a system1 in use4 ,,history3 ,several years ago ,i published a ,history of ,automatic ,electric and ,electrically ,controlled ,fluid ,pressure ,signal ,systems for ,railroads1 the only authentic history ever published on the subject4 ,this was written and published at the instance of engineering friends1 in the interest of indisputable historical accuracy4 ,telephone ,experiments #ahgf4 ,as a matter of more or less interest ,i may here state that ,i carried on a conversation by telephone1 in #ahgf1 through a railroad track1 the circuit consisting of the two rail lines constituting a closed circuit signal block4 #ahgg-h4 ,delivered numerous illustrated lectures on the telephone1 and at this time discovered the principle of the wireless telephone and actually transmitted speech clearly back and forth across an open space of several inches to and from a telephone having but one terminal grounded and the other free in the air4 ,the free1 uninsulated wire 7except at supports7 extended several hundred feet through the air4 ,the instruments used were large magneto telephones of my own special designing1 and made by me for the special purpose of illustrating lectures4 ,no battery was used4 ,electric ,railway ,systems ,outside of automatic signaling ,i have done considerable work along original electrical lines4 ,in addition to other work of importance ,i have for more than fifteen years devoted much time to developing a radically new departure in electric railroading4 ,on this system ,i have applied for more than twenty patents1 extending over a series of years1 fourteen of which patents have already been issued4 ,what ,this ,system ,accomplishes #a4 ,the third rail or contact conductor is made in sections or blocks of any desired length1 which sections are normally dead but become automatically alive when a train enters thereupon1 and dead when the train leaves the section4 #b4 ,when a train enters upon a section or block it prevents the section back of it from receiving working current4 ,thus any number of trains following each other will each be deprived of working current when the length of a block back of the train ahead of it1 whether that train be running or standing still1 thus preventing collisions4 #c4 ,a train approaching a switch or drawbridge is automatically arrested the length of a block away from the block containing the switch or draw before a bolt can be withdrawn or a lock released in the latter4 #d4 ,no possibility of interference between a possible wandering propulsion current and the functions of any other current4 #e4 ,all currents used may be of the same or have any combination of different characteristics4 ,the system is elaborate1 providing for safety on and off the trains1 economy of current1 simplicity and certainty in action1 dispenses largely with electrolytic action1 and when alternating propulsion current is used the return is confined to the length of the block4 ,it is believed that the system will prevent all danger to passengers and trains from the direct action of the propulsion current4 ,president ,roosevelt called the attention of the ,interstate ,commerce ,commission to my electrical and mechanical inventions for making railroading safe4 ,mechanical ,engineering ,i have done considerable original work in mechanical engineering4 ,in this connection ,i may mention the well known ,robinson ,radial ,car ,truck1 which is in quite extensive operation on electric railways4 ,this is the only car truck1 ,i believe1 ever designed and constructed on correct mechanical principles4 ,it is so constructed that every axle in the car or train becomes exactly radial to any curve around which it passes1 all the axles becoming parallel on straight lines only4 ,this prevents wear and tear and grinding and derailment on curves4 ,it also greatly economizes current4 ,one of these radial cars1 in ,st4 ,louis1 having a #bh-;ft4 body1 exclusive of platforms1 equipped with a radial truck having a #ae-;ft4 wheel-base and two motors1 stopped in the middle of a street corner curve and started with the same power as on a straight line1 as shown by careful tests with volt and ammeters4 ,the test was made by officials of the company without my knowledge at the time4 ,i believe this is the coming truck for electric locomotives4 7,i forward by same mail a catalogue of the ,robinson ,radial ,car ,truck1 fully illustrated1 for the information of the ,board47 ,coaster ,hub ,i am also the inventor of the back pedal braking and coasting bicycle hub1 which has been in general use for many years4 ,my application for a basic patent covering this hub has been pending in the ,patent ,office for twelve years1 held back nine years by interference litigation in the ,patent ,office1 owing to an effete interference system which has no apology to offer to justify its existence4 ,turbine ,engines ,in turbine engines ,i have made some important improvements4 ,in one the engine is reversible by the movement of a single lever in either direction4 ,in a second the steam is utilized a second time under conditions doubling the original efficiency1 and balancing the end thrust perfectly4 ,in a third improvement the engine develops more than three times as much power as any other turbine of its class occupying the same floor space4 ,patents allowed but not yet issued4 ,i figure that ocean steamers should furnish a large field for these machines4 ,respectfully submitted1 7,signed7 ,,william ,,robinson4 #bgf ,stuyvesant ,ave41 ,brooklyn1 ,n4,y4 ,part ,,ii ,,william ,,ashbridge ,,baldwin ,the progressive ideas of ,william ,ashbridge ,baldwin were responsible for the first tests of the closed track circuit under actual operating conditions4 ,it was through his confidence in this invention of ,dr4 ,william ,robinson that the possibilities of the application of the closed track circuit to the safety of train operation was proved4 ,mr4 ,baldwin1 at the time the first signal installations were made at ,kinzua1 ,pa41 and ,irvineton1 was general superintendent of the ,philadelphia and ,erie1 now part of the ,northern ,grand division1 ,central region1 ,pennsylvania ,system1 and because he made possible the development of signaling to its present standard by his interest and active co-operation in the #gj's in making train movements safer1 it is but fitting that he should be given a place in the memorial to ,dr4 ,william ,robinson4 ,illustration3 ,tracks and ,location of ,electric ,signals ,dr4 ,robinson's ,patent ,kinzua ,pa4 #ahgb-ahgc4 ,illustration3 ,tracks and ,location of ,electric ,signals ,dr4 ,robinson's ,patent ,irvineton #ahgb-ahgc4 ,before stating ,mr4 ,baldwin's railroad activities it will be well to describe briefly the way in which he became interested in ,dr4 ,robinson and his work4 ,dr4 ,robinson shortly after being graduated from college began work on a signal system to prevent train accidents which were of numerous occurrence1 and made a model of his open wire system which was exhibited at the fair held by the ,american ,institute of ,electrical ,engineers in ,new ,york in #ahgj4 ,at the close of the fair1 he sent out circulars to officers of various railroad companies explaining his system4 ,the one received by ,mr4 ,baldwin interested him to such an extent that he arranged for ,dr4 ,robinson to make an installation at ,kinzua1 ,pa41 in #ahgj4 ,this installation was of the normally open wire circuit controlled by track levers4 ,after the installation1 ,dr4 ,robinson seeing that it had many serious defects began studying how to correct them4 ,this was accomplished by the invention of the closed track circuit4 ,he then exhibited his closed track circuit system of signaling at the ,state ,fair held at ,erie1 ,pa41 in #ahgb1 where he had his track circuits operating under water in a long tank4 ,dr4 ,robinson had previously explained the principles of the closed track circuit to ,mr4 ,baldwin who requested him to make such an installation at ,kinzua1 ,pa41 in place of the open wire circuit4 ,after this was in service1 ,mr4 ,baldwin ordered another installation to be made at ,irvineton1 ,pa41 and because of the good service rendered1 this signal soon came to be called the ,old ,reliable by the locomotive enginemen4 7,a picture of this signal appears in ,part ,i47 ,old ,employees ,describe ,first ,installations ,through the courtesy of ,a4 ,j4 ,whitney1 general superintendent1 ,northern ,grand division1 ,central region1 ,pennsylvania ,system1 and ,a4 ,h4 ,rudd1 chief signal engineer of the ,pennsylvania ,system1 the following information was developed from interviews with ,wm4 ,metzger1 #hh years old1 of ,irvineton1 ,pa41 once an engineer on the ,philadelphia ,erie2 ,associate ,judge ,j4 ,w4 ,hughes1 of ,warren1 ,pa41 formerly yard master at ,irvineton2 ,john ,christie1 car inspector at ,irvineton1 and ,j4 ,c4 ,curtis1 formerly a train dispatcher on the ,renovo division4 ,about #ahgb1 ,dr4 ,robinson1 who probably came from ,altoona1 erected a signal governing westward movements1 near ,irvineton4 ,this signal was located just west of ,irvine ,run bridge1 on the north side of the main track 7this track is now an eastward track71 in a small frame building adjacent to the track and was electrically operated back of a circular opening about two feet in diameter1 by display of a red flag during the day and a light in the rear of the flag by night4 ,a bell was also located in the signal shanty and another bell in the telegraph office of the station1 located at the junction of the two railroads 7see sketch74 ,a trip device1 operated by the wheel flange1 forced contact with wires carried on the telegraph poles and operated the signal and bell in the signal shanty as well as bell in the telegraph office4 ,the signal was known as the ,old ,reliable and the words ,dr4 ,robinson's ,patent were painted around the circular opening4 ,another pair of signals was installed by ,dr4 ,robinson at ,kinzua1 now ,ludlow1 for protection of trains stopping at ,kinzua 7,ludlow7 station4 ,these signals were operated by overhead wires as at ,irvineton4 ,when a train was opposite one of the signals1 it set both signals to red indication by operating a red flag within a circular opening in the daytime and a light in the rear of the flag at night4 ,a loud gong was also installed in each shanty which rang coincident with the signal going to the red indication4 ,when the rear of the train passed the signal in advance both signals returned to clear and the bells stopped ringing4 ,this system was operated with batteries and was removed in less than a year on account of the difficulty of maintaining the batteries4 ,biographical ,sketch of ,w4 ,a4 ,baldwin ,the biographical sketch of ,mr4 ,baldwin1 as given below is taken from the ,biographical ,directory of the ,railway ,officials of ,america--,edition of #aijf4 ,,baldwin1 ,,william ,,ashbridge1 president1 ,cleveland ,marietta ,ry4 ,office1 ,pittsburgh1 ,pa4 ,born ,june #bh1 #ahce1 at ,philadelphia1 ,pa4 ,entered railway service ,november1 #ahea1 as chainman1 engineer corps1 ,coal ,run ,road1 in ,schuylkill county1 ,pennsylvania1 since which he has been consecutively1 ,march1 #aheb to #ahed1 assistant engineer on the same road2 #ahed to ,march1 #aheg1 leveler and topographer1 ,lackawanna ,bloomsburg ,road2 ,march1 #aheg1 to ,december1 #aheh1 assistant engineer1 leveler and topographer1 ,honduras ,inter-,oceanic ,road1 at ,honduras1 ,central ,america2 ,december1 #aheh1 to ,november1 #ahei1 clerk to superintendent1 ,western division1 ,pennsylvania2 ,january1 #ahfj1 to ,february1 #ahfb1 assistant engineer1 ,pennsylvania2 ,february #g1 #ahfb1 to ,march #ac1 #ahfh1 superintendent1 ,western division1 ,philadelphia ,erie 7,pennsylvania1 lessee72 ,march #ac1 #ahfh1 to ,may #g1 #ahgj1 assistant general superintendent1 same road2 ,may #g1 #ahgj1 to ,october #a1 #ahgc1 general superintendent1 ,philadelphia ,erie division1 ,pennsylvania2 ,october #a1 #ahgc1 to ,september #a1 #ahha1 general superintendent1 same division1 same road1 and ,s4 ,s4 divisions1 ,northern ,central ,ry42 ,september #a1 #ahha1 to ,may #a1 #ahhb1 manager1 ,pennsylvania ,co41 and ,pittsburgh1 ,cincinnati ,st4 ,louis ,railway ,lines2 ,may #a1 #ahhb1 to ,march #ca1 #ahhh1 manager1 ,pennsylvania ,co4's lines2 ,april #a1 #ahhh1 to ,april1 #ahib1 vice-president and general manager1 ,buffalo1 ,rochester ,pittsburgh2 ,november1 #ahic1 to date1 president1 ,cleveland ,marietta ,ry42 ,november1 #ahic1 to ,december #ca1 #ahii1 also general manager same road4 ,retired from that road on ,april #cj1 #aijf1 at the age of #gj years1 under the pension rules of the ,pennsylvania ,lines ,west of ,pittsburgh1 of which the ,cleveland ,marietta was a part4 ,mr4 ,baldwin died on ,february #ag1 #aiaa1 at ,sewickley1 ,pa41 at the age of #ge4 ,his obituary1 as appearing in the ,railway ,age for ,february #bd1 #aiaa1 appears below4 ,,william ,,ashbridge ,,baldwin1 former president of the ,cleveland ,marietta1 which is now a part of the ,pennsylvania ,system1 died in ,sewickley1 ,pa41 ,february #ag4 ,mr4 ,baldwin was born on ,june #bh1 #ahce1 at ,philadelphia1 and began railway work in ,november1 #ahea1 with a party of engineers making surveys in ,schuylkill ,county1 ,pa4 ,in ,march1 #aheg1 he went to ,honduras1 ,central ,america1 as assistant engineer1 leveler and topographer on the ,honduras ,inter-,oceanic ,railway4 ,in ,december of the following year he returned to this country and entered the employ of the ,pennsylvania ,railroad4 ,in #ahfb he was appointed superintendent of the ,western division of the ,philadelphia ,erie4 ,by ,may1 #ahgj1 he had become general superintendent of the ,philadelphia ,erie division1 and in ,september1 #ahha he was appointed manager of the ,pennsylvania ,lines ,west of ,pittsburgh4 ,in #ahhh he went to ,buffalo1 ,rochester ,pittsburgh as vice-president and general manager1 but five years later he returned to the ,pennsylvania ,system and was made president of the ,cleveland ,marietta4 ,part ,,iii ,,the ,,track ,,circuit ,perhaps no single invention in the history of the development of railway transportation has contributed more towards safety and despatch in that field than the track circuit4 ,by this invention1 simple in itself1 the foundation was obtained for the development of practically every one of the intricate systems of railway block signaling in use today wherein the train is1 under all conditions1 continuously active in maintaining its own protection4 ,in other words1 the track circuit is today the only medium recognized as fundamentally safe by experts in railway signaling whereby a train or any part thereof may retain continuous and direct control of a block signal while occupying any portion of the track guarded by the signal4 ,to ,mr4 ,william ,robinson the ,patent ,office records concede the honor of having devised the first practical track or ',rail circuit'4 ,this comprised what is termed the closed track circuit4 99 99 99 ,closed track circuits are very reliable1 wholly safe in principle1 and simple of application and maintenance4 ,the above paragraphs1 quoted from the third annual report of the ,block ,signal and ,train ,control ,board to the ,interstate ,commerce ,commission under date of ,november #bb1 #aiaj1 ably express in a few words what the invention of the track circuit has meant to the railroads of this and other countries4 ,in order1 however1 that those who are not familiar with the principles of the track circuit may have some general knowledge of them1 a simple1 non-technical description is given1 as prepared some years ago by ,mr4 ,j4 ,p4 ,coleman1 of the ,union ,switch ,signal ,company4 ,historical information on the development and use of direct current and alternating current track circuits for roads using electricity for propulsion purposes and those using steam will be found in a report on this subject made by ,committee ,x to the ,railway ,signal ,association in #aiaj4 ,the ,rail ,circuit ,principle ,by ,j4 ,p4 ,coleman4 ,assuming that it is clearly understood that the current is generated at the battery2 that it flows from thence through the conductors 7of which the coils of the magnet form part7 and back again to the battery1 and that the magnet is simply a device interposed in the circuit for the purpose of transforming electrical energy into mechanical 7magnetic7 energy1 and that the latter can exist in an electro-magnet only with the presence of the former1 we are now prepared to make clear the principle of an electric track section4 ,to assist in this1 let us state an invariable law governing the flow of currents3 ,if two or more paths be presented an electric current1 it immediately becomes divided1 and flows in each in quantities directly in proportion to the conductivity of each4 ,the unit of electrical resistance1 whereby the comparative merits of various materials and sizes of materials as conductors are designated1 is called an ohm1 7just as the unit of lineal measurement whereby the comparative lengths and sizes of various objects are designated1 is termed a foot7 and we will therefore use that term in reference to the resistance of a conductor4 ,illustration3 ,fig4 #a ,figure #a represents an ordinary gravity battery1 the conductors from it1 and the electro-magnet to which they connect2 also the armature as attracted by the magnet and overcoming the spring which tends to withdraw it from the magnet4 ,now1 as long as the current flows through the magnet1 this condition of things remains unaltered2 but let a second path be presented to the current several hundred times less in resistance than the original one1 and the result is that several hundred parts of the current will leave the magnet for the short circuit1 and consequently leave so little remaining in the original one that the effect will be practically to demagnetize the magnets4 ,illustration3 ,fig4 #b ,figure #b will render this very apparent if we will assume the wire of the magnet ,r to possess a resistance of #aj ohms1 and the conductors themselves a resistance so low as to be inappreciable and unworthy of consideration4 ,illustration3 ,fig4 #c ,illustration3 ,fig4 #d ,now1 assume the current to be flowing and the magnet to be charged1 and let us take a piece of metal which has an electrical resistance of #a_/ajj of an ohm1 and lay it across the conductors at any point between the battery and the magnet4 ,the result is1 that instead of flowing through #aj ohms resistance via the magnet1 it follows the invariable rule1 and takes that offering but #a_/ajj of an ohm2 or1 more to the point1 if we assume the conductors referred to to be one mile of steel rails each 7,fig4 #c71 and again leave their resistance 7which would be about one ohm each7 out of consideration entirely1 leaving that of the magnet as first stated1 and assume the bar of #a_/ajj of an ohm to be an axle and pair of wheels 7a7 of a train 7,fig4 #d71 which possess the same resistance1 we can readily see that the result would be exactly the same1 i4e41 instead of all the current passing through the magnets1 as when the rails were unoccupied1 the presence of the wheels upon them would cause #iii_/ajjj of the current to leave the magnet and pass through them2 they offering but #iii_/ajjj of the resistance of the magnets1 and thus leaving but #a_/ajjj of the whole current passing through them1 which being so small a part of so feeble a current is imperceptible and without sufficient influence to hold the magnet charged4 ,therefore1 it follows that the instant that a pair of wheels enters upon a pair of rails which thus form part of the conductors of an electrical current holding charged a magnet1 that magnet becomes practically demagnetized1 and consequently loses all power to overcome any opposing force in its armature4 ,when the armature of a magnet is arranged upon a small lever1 by motion of which a second circuit is closed or opened1 or two or more circuits are otherwise controlled1 the entire device is termed a relay4 ,in all forms of this instrument1 as is the case with almost every other electrical instrument1 the armature is so arranged as to fall by gravity1 or by tension of a small spring suitably arranged1 away from the cores of the magnets when they become demagnetized4 ,illustration3 ,fig4 #e ,when switches are included in a track section 7,fig4 #e71 it becomes necessary for safety to have them control the track section in such a way that unless they are properly set 7and locked1 if desired7 for the main track1 the continuity of the rail circuit is interrupted and the signal is thereby held at danger4 ,to render more certain this result1 the circuit controller 7switch box7 at the switch is arranged in such a way that the track circuit is not only interrupted beyond the switch1 but is also short-circuited by it when the switch is not properly set4 ,it is also necessary for safety that the side track from the switch points back to the fouling point 7,fig4 #e7 be included in the track section3 thus insuring that all trains on these tracks are out of danger of collision with the main track when a clear signal is displayed on it4 ,in dividing tracks into distinct electrical sections1 it becomes necessary to insulate the rail ends at the terminal of each1 from those of the adjacent sections4 ,if this were not done the current of each section would traverse the next1 and continue on indefinitely1 influencing each other so as to interfere with or totally prevent the operation of all4 ,in order that we may fully comprehend the nature of an insulation1 let us make clear a few facts concerning conductors in general4 ,all materials conduct electricity to a certain extent2 but some with much more freedom than others4 ,thus1 silver1 copper1 gold1 zinc1 platinum1 iron1 steel1 mercury1 and other pure metals permit the passage of an electric current through them with but slight resistance1 7although all offer a certain amount17 and are therefore termed conductors4 ,the following liquids are classed as conductors3 concentrated and diluted acids1 saline liquids and water1 although they are much less efficient as such than the metals4 ,to this list might be added the earth itself and the various ingredients forming it1 the nature of which ingredients determines very much its efficiency as a conductor4 ,thus at points abounding in mineral deposits the earth would be far superior as a conductor to those parts in which none exist1 but at best should be regarded as a poor conductor4 ,next comes a class of materials which offer a great resistance to the current1 and which from that reason are termed non-conductors1 or insulators2 of this class1 rubber1 glass1 leather1 resin1 wood1 brimstone and dry air are the most common4 ,wood being a non-conductor1 it is very evident that the cross-ties under the steel rails form an insulation between them and the ground2 also1 that if a piece of the same or similar material be placed between the rail ends1 and that if two other pieces of sufficient strength be substituted for the iron fish-plates at that point1 a secure insulation will be formed between the rails4 ,it is precisely in this way that the insulation of one rail from another is effected 7,fig4 #f7 and the long1 practical use of many hundred joints of this sort1 has proved it to be a method both economical and thoroughly efficient4 ,illustration3 ,fig4 #f ,a much more secure joint1 however1 is obtained by insulating the existing iron fish-plates from the rails by means of heavy fiber plates1 and their bolts from the rails by fiber bushings 7,fig4 #g74 ,while this method is superior to the first mentioned one in that it makes a more secure rail joint1 it is no more efficient as an insulation4 ,illustration3 ,fig4 #g ,one would naturally suppose that owing to the large surface of contact existing between the rails and their connecting or fish-plates1 and from the apparent security of that contact obtained by the bolts through them1 no trouble would be experienced by the current in passing from one rail to the other4 ,this1 however1 is not the case1 as the bolts and even the plates themselves frequently become loose1 even when provided with the best of nut locks1 and the rust and dirt settling between them and the rails oftentimes increase the resistance of a track section to a serious extent4 ,again1 even when tightly bolted and locked1 these plates form but an imperfect contact1 owing to the scale or rust upon them4 ,therefore1 to insure that the resistance of a track section may be as low and as constant as possible1 we have found it absolutely necessary to connect each two adjacent rail ends together by means of a short piece of very strong wire 7,fig4 #h74 ,illustration3 ,fig4 #h ,these wires are termed track wires 7bond wires7 and are provided with a button-head rivet at each end1 which is securely soldered thereto1 for the purpose of securing them to the rails4 7,bond wires are now attached to the rails by channel pins or are welded on47 ,the connections from the rails to the battery and relay of a track section are secured to the rails in the same manner4 ,the battery is usually located in a chute or well sunk in the ground at the terminal of each section1 which is provided with an elevator in which the battery is placed and by which it may be raised and lowered at will4 ,all wires when placed underground are run in grooved lumber in order that they may be secure from injury4 ,even in very wet or snowy weather a single jar of gravity battery is generally found to furnish sufficient current to properly work the relay at the other end of any section less than three-quarters of a mile in length2 although it frequently happens on longer sections and occasionally on those of ordinary length that two jars are necessary4 ,a greater number of jars is never advisable since by increasing the intensity of the current1 the liability of its leaking from one rail to the other during wet weather is correspondingly increased1 and as this is attended with some uncertainty in the working of the relay of the section--due to the varying intensity of the current--it should be carefully guarded against4 ,as two jars of gravity battery are not sufficient to operate a signal1 lock1 bell or any similar instrument with any degree of certainty1 it becomes necessary to have a second set of batteries of a greater number of jars for that purpose4 ,the armature of the magnet controlled by the track section is therefore made to control a second circuit using a battery of this sort 7,figs4 #c1 #d and #e7 and which includes the magnet of the signal mechanism4 ,the use of a relay on a track section is therefore necessary2 and when it becomes necessary to control two or more devices1 each requiring independent circuits1 by one track1 the use of a relay is indispensable4 ,track ,circuit ,characteristics ,while the fundamental principles of the track circuit are the same today as they were when it was originally invented by ,dr4 ,robinson in #ahgb1 it has been found that it is not as simple a device as was formerly supposed to be the case and many problems have arisen which have required and is requiring the careful study of the signal engineers4 ,accordingly1 it is well to present briefly some of the track circuit characteristics as they are known today4 ,in the following presentation1 information has been collected from many different sources1 including abstracts from papers presented on the track circuit by ,mr4 ,a4 ,r4 ,fugina1 signal engineer1 and ,mr4 ,j4 ,b4 ,weigle1 signal inspector on the ,louisville ,nashville4 ,there are two general classes of track circuits1 direct current and alternating current1 which may be further subdivided between single or double rail circuits4 ,the essential feature of the track circuit is the insulation of each section of track from the adjoining sections4 ,each rail in the section is connected to the one adjoining by bond wires1 for the purpose of making a continuous conductor from one end of the section to the other4 ,rail ,bonding ,under the present methods of bonding1 the angle bar carries the greater part of the current1 and bond wires frequently carry as little as #bj per cent4 of it and sometimes even less4 ,the rail resistance is lowest with new rails1 but it gradually gets higher1 due to rust and dirt formations between the angle bar and the rail4 ,but even with new rail1 the rail resistance varies greatly at different periods and even at different times during any twenty-four hours4 ,this variation is entirely due to the fact that the angle bars carry more of the current than the bond wires1 and that the bond wires under any condition are only large enough to carry the smaller part of the current from the battery4 ,the lower the resistance of the bonds the less variable will be the rail resistance4 ,the resistance of the angle bars increases greatly as rail resistance increases1 as a result of which the angle bars rapidly carry less of the current4 ,it is not infrequent to find the rail resistance to be as high as #j4bj ohms per #a1jjj ft4 of track1 and we have known it to run as high as #j4bfd in new rail1 where especial attention had been given to obtaining as good bonding as possible4 ,under such conditions the angle bar carries very little of the current1 the capacity of the bond is not sufficient to carry the current1 and the net result is a failing track circuit1 which is probably attributed to bad ballast1 zinc treated ties or other causes4 ,the principal defect in the track circuit is that of improper bonding4 ,the only explanation as to why ,no4 #h iron wires became standard for bonding appears to be that the bond wires were cut from this size iron telegraph wire which was in general use at the time rails began to be bonded4 ,it is important to obtain better bonding to obtain a minimum constant rail resistance4 ,it has been recommended that3 ,first--,the use of galvanized wire bonds should be eliminated4 ,second--,forty per cent4 copper clad bond wires should be used as a temporary expedient to replace galvanized bond wires4 ,third--,except for theft and crystallization1 copper bond wires would be much more advisable4 ,fourth--,larger bond wires should be used1 these bonds to be at least equal in carrying capacity to two #df-;in4 ,no4 #f solid copper or to two ,no4 #b1 #dj per cent4 copper clad wires4 ,until recently it has been the general opinion of all experts on the track circuit that the rail resistance was rather an unimportant factor and that1 as a general rule1 the change in rail resistance could be disregarded in making track circuit investigations and calculations4 ,many bad track circuit conditions have been laid to bad ballast conditions1 zinc treated ties1 wet track1 etc41 which1 if carefully analyzed1 would have shown the trouble to be due to extremely high rail resistance4 ,these faulty conclusions are being drawn nearly every day4 ,single rail track circuits1 so called from the fact that but one rail is insulated1 are also used4 ,installations of this kind are made to avoid the expense of two insulated joints or where one rail is needed for another circuit4 ,such track circuits are more liable to failure than those having both rails insulated for the reason that the break-down of one insulated joint will extend the circuit beyond the proper limit and cause interference of neighboring circuits or extended shunting of the relay1 due to the presence of a train beyond the insulated joint4 ,a track circuit may be made to perform two separate functions in which the direction or polarity as well as the presence of current is made use of in the relay1 provided the first or principal function actuated by the presence or absence of current does not interfere with the secondary function1 actuated both by the presence of current and its polarity4 ,where switches occur in a track circuit1 special means must be employed to prevent short-circuiting through the switch rods and leakage of current to the turn-out rail4 ,the usual method is the use of insulated switch rods with insulated joints in the leads of the turnout and at the fouling point of the turnout4 ,the switch points are bonded to the stock rails to insure shunting by a pair of wheels on any part of the track4 ,none of the methods employed in running track circuits through switches show any protection against an open switch4 ,in order to obtain this protection a switch instrument or switch box is used4 ,this consists of a device with electrical contacts1 the whole mounted on a switch timber and connected to the switch point by means of a rod so arranged that when a switch slips open or is thrown open the movement of the rod actuates contacts which1 on being closed1 form a closed path from one rail to the other through wires connecting the rails to the contacts1 thus when the contacts are closed by a switch being opened1 the same effect is produced as if a train was on the circuit1 shunting it out4 ,on electrically operated roads where tracks are bonded for the return propulsion current with heavy copper bonds1 no additional bond wires are necessary4 ,the ,track ,battery ,the usual form of track circuit has a primary battery at one end of the insulated track section1 with the positive terminal of the battery connected to one rail and the negative terminal to the other1 while a relay at the other end of the section is connected to the rails in a similar manner4 ,current flows from the positive side of the battery through the one rail1 the relay and the other rail back to the battery1 thus keeping the relay energized4 ,for d4c4 track circuits1 four types of cells have been used to a greater or less extent1 the gravity cell2 ,lalande 7soda7 cell2 storage cell and dry cell4 ,the gravity cell has a voltage of about #j4h or #j4i volts1 the resistance varying with the manner in which the cell is maintained and averaging about #c ohms4 ,it will remain active for long periods on closed circuits without appreciable polarization4 ,because of this high internal resistance usually no external resistance is necessary to be connected between it and the rail of the track4 ,the e4m4f4 of the ,lalande 7soda7 cell may vary from about #j4fg volts to #j4hh volts while the internal resistance will range between #j4jai ohm to #j4d ohm4 ,because of the low internal resistance of these cells it is necessary to use an external resistance of the proper value between the cell and the rail4 ,the storage cell is made in various capacities and a fully charged cell on open circuit has a voltage of approximately #b4a volts which1 when placed on discharge1 becomes approximately #b volts and drops to about #a4h volts when completely discharged4 ,the voltage in this type of cell varies with the density of the electrolyte and to a certain extent with temperature4 ,it has practically a negligible internal resistance and it is also necessary to use an external resistance in the leads between the cell and the track to prevent a flow of excessive current when a train occupies the track4 ,the dry cell is used only in emergency cases or occasionally for open circuit track circuits of #b or #c rail lengths1 which are sometimes used as annunciator starts to announce the approach of a train to a tower-man4 ,it is designed primarily for open circuit work and will polarize when current beyond a certain figure is drawn continuously from it4 ,the ,track ,relay ,the track relay is a development of the instrument of the same name used in telegraph service4 ,it consists of an electro-magnet of the horseshoe type with a pivoted armature1 carrying one or more fingers for making or breaking electric circuits for the control of signal apparatus4 ,track relays with resistances of #b and #d ohms are usually employed4 ,from experience with two-ohm relays on the ,l4 ,n41 covering a great many of them on all kinds of circuits1 the following conclusions are reached3 ,the two-ohm relay is more suitable for general use on track circuits than the four-ohm1 provided not less than the ,r4,s4,a4 recommended limiting resistance is used between the battery and track4 ,the two-ohm relay will operate satisfactorily where the four-ohm will not on bad track circuits1 and with considerably less current consumption4 ,the two-ohm relay will operate equally as well on good track circuits of average length as the four-ohm1 there being little difference in current consumption on this class of circuit4 ,under the same conditions longer track circuits may be operated with the two-ohm relay4 ,the two-ohm relay is at least as safe as the four ohm4 ,it should be thoroughly understood that it is as important with the four-ohm relay as it is with the two-ohm relay to have not less than the ,r4,s4,a4 recommended limiting resistance between the battery and track4 ,this is important with any kind of low internal resistance battery1 and under certain conditions with gravity battery also4 ,in one case assume a train to be passing from the relay end to the battery end of a track section and in the other case from the battery end to the relay end4 ,the effect accomplished is the same except that the relay will not release so quickly when the train passes from the battery end towards the relay end1 and this is in part due to the self-induction of the circuit through the relay coils1 the rails and the axles of the train4 ,it is due more1 however1 to small current leakage from the adjacent section and the effects of stray currents which are always present to a greater or less degree4 ,a broken rail will also generally open the circuit and de-energize the relay4 ,circuits for the control of the various signal devices are broken through the contact points of the track relay4 ,track ,circuit ,maintenance ,cross ties have a relatively high resistance to the passage of electric current1 but when a large number connect the rails many multiple paths are introduced into the circuit through which the current may flow from one rail to the other1 and1 considering them as a whole1 the resistance they offer to the passage of the current reaches a relatively low value4 ,consequently there is always a current leakage from rail to rail through the cross ties and ballast4 ,every effort should be made to secure and maintain the best ballast and drainage possible on d4c4 as well as a4c4 track circuits4 ,cinders1 dirty sand1 soft water-logged ties and ballast not well cleaned away from the base of the rail will produce track circuit trouble1 particularly during wet weather1 while good rock ballast1 sound ties and clean track give the greatest efficiency4 ,the use of ties freshly treated with zinc chloride also reduces the ballast resistance4 ,if too many such ties are used in a track circuit the current leakage between rails becomes so great that not enough current reaches the relay to hold it closed1 the effect being the same as if a train is on the track circuit shunting out the relay4 ,for good results1 the number of zinc-treated ties installed per year in any track circuit should not be greater than #ae per cent4 of the total number of ties in that circuit4 ,track ,circuit ,troubles ,some of the common track circuit ailments are relay and track battery troubles1 defective track connections1 poor bonding and broken rails1 short circuits or shunts1 excessive leakage and defective insulated joints1 all of which will cause the signals to be set in the danger position1 while defective relays1 foreign current and poor wheel contact may result in a false proceed signal indication with a train in the block section4 ,it was the quite general practice to operate bad track circuits by piling on gravity battery1 either in multiple or multiple-series arrangements to obtain operating results without any regard to the safety of the circuit and1 no doubt1 many false proceed failures were caused thereby4 ,the effect of temperature changes on track circuit operation are of considerable importance4 ,the track relay1 which is generally housed in a cast or sheet iron box1 probably is affected more by changes in temperature than any other part of the track circuit4 ,the resistance of a #b-ohm relay1 which is #b ohm at #gj degrees ,f41 will be #b4bb ohm at #abj degrees ,f41 and #a4fi ohm at #j degrees ,f41 a variation of 4#ec ohm4 ,the pick up and release of the relay1 4#b and 4#a volt1 respectively1 at #gj degrees ,f41 will be 4#bb and 4#aa volt at #abj degrees ,f41 and 4#ag and 4#jhe volt at #j degrees ,f4 ,a relay1 with a normal resistance of #d ohm at #gj degrees ,f41 will be #d4de ohm at #abj degrees ,f4 and #c4ch ohm at #j degrees ,f41 a variation of #a4jg ohm4 ,the pick up and release1 4#c and 4#ad volt1 respectively1 at #gj degrees ,f41 will be 4#cc and 4#af volt at #abj degrees ,f4 and 4#be and 4#ab volt at zero4 ,the point which is intended to be brought out by these figures is that when the temperature of the relay increases1 a correspondingly higher voltage is required to pick up the armature1 and when the temperature decreases the armature will hold up with lower voltage across the coils4 ,this indicates that a track relay is more liable to fail to release due to an imperfect train shunt in cold weather than at any other time4 ,some of the best preventatives that may be provided to guard against false proceed signals due to track relays failing to release with a train in the circuit1 are3 #a4 ,use as much resistance as practicable between battery and track4 #b4 ,use low resistance bond wires1 and maintain bonding in good shape4 #c4 ,keep ballast well cleared from contact with rails4 #d4 ,maintain insulation in insulated track joints in good condition4 ,aside from these simple remedies no definite rule can be given to combat foreign current4 ,if it is so troublesome that these methods do not overcome it1 the circuit affected must be carefully studied to determine the source of the foreign current and its path to the rails1 then special means can usually be provided to overcome it4 ,ballast ,resistance and ,leakage ,the importance of ballast resistance has long been recognized1 and this always has been considered the great variable1 whereas1 investigations show that the ballast resistance is at least no more variable than the rail resistance1 and that of the two it is more important to reduce the rail resistance to a minimum1 and especially to establish it as a constant4 ,when the ballast leakage problem was first taken up 7on the ,l4 ,n471 various kinds of ballast were measured in both wet and dry weather1 the intention being to determine the lowest possible resistance per #ajjj ft4 for each kind of ballast4 ,it was proposed in this way to establish a standard minimum resistance per #ajjj ft4 for each kind of ballast4 ,for instance1 if a number of measurements in wet weather showed #h ohms per #ajjj ft4 as a minimum for track circuits with crushed rock ballast1 it was the intention to adopt #h ohms as the standard minimum ballast resistance per #ajjj ft4 for all track circuits where crushed rock ballast was in use4 ,if a number of wet weather measurements showed #d ohms per #ajjj ft4 as a minimum for cinder ballast1 it was the intention to adopt #d ohms as the standard minimum ballast resistance per #ajjj ft4 for all track circuits where cinder ballast was used4 ,it was the intention to follow out the same process and establish a standard for all kinds of ballast in use4 ,this was soon found to be impracticable4 ,after making many ballast resistance measurements1 it was noticed that the variation of the resistance on any track circuit1 as between wet and dry weather1 generally followed quite a definite rule4 ,for instance3 ,if the resistance per #ajjj ft4 of dry ballast was found to be #bh ohms or more1 it would be not less than #h ohms per #ajjj ft4 when wet2 or if resistance of dry ballast was found to be between #bb and #bh ohms per #ajjj ft41 it would be not less than #f ohms per #ajjj ft4 when wet4 ,once a relay is picked up or energized1 but a small amount of current is required to maintain it in that condition4 ,this is one reason why it is important to keep the ballast clear of the rails and it is because of the condition which may cause a relay to remain energized that rules are in force requiring the signalmen to disconnect a track relay when track forces are changing out rails4 ,combined ,rail and ,bond ,wire ,resistance ,on circuits newly bonded with two #df-;in4 galvanized iron wires a joint1 the combined rail and bond wire resistance was found 7on the ,l4 ,n47 to vary from 4#jb ohm per #ajjj ft4 of track on some circuits to 4#bfe ohm on others1 a difference of over #acjj per cent4 ,this was rather puzzling4 ,after a great many measurements had been made on different circuits it was found that no two measurements gave the same results1 notwithstanding the fact that in many circuits the size of rail1 length of bond wires1 and age of bonding were exactly the same4 ,on account of the bonding being new and the channel pins well driven1 the contact between the bond wire and rail was above suspicion4 ,the only other part of a track circuit that could possibly be the cause of this difference was in the contact between the angle bars and rails1 and this later proved to be the case4 ,actual measurements made in the field proved that when the rail is new and the joint bolts tight1 nearly all of the current flowing from rail to rail passes through the angle bars1 whereas when the rails get old a coating of rust and dirt forms between the rail and angle bars1 forcing practically all of the current through the bond wires4 ,on most of the circuits measured on the ,l4 ,n4 the combined rail and bond wire resistance was found to be less than 4#a ohm per #ajjj ft4 of track1 although many were found to be between 4#aj and 4#cj ohm per #ajjj ft4 ,it is interesting to note that two circuits were found bonded with two #eb-;in4 iron wires1 for which the combined rail and bond wire resistance measured 4#daj ohm1 and that by adding two #dj per cent4 copper clad bond wires to each joint the combined resistance was reduced to 4#add ohm4 ,the ,growth of the ,track ,circuit ,unfortunately there exists little or no data regarding the mileage of track circuits installed from the time the first installation was made by ,dr4 ,robinson at ,kinzua1 ,pa41 and ,irvineton up to about #aije4 ,during the period between ,january #a1 #aije1 and ,september #cj1 #aijf1 the total automatic block signal mileage installed was #a1gaj4f1 which brought the total up to #f1hbf4i for the ,united ,states4 ,between ,september #cj1 #aijf1 and ,january #a1 #aijh1 #c1igf4a miles of automatic signals were installed1 which increased the above total to #aj1hjc4j miles4 ,the ,block ,signal and ,train ,control ,board1 seeing the need for accurate data in the signal field1 started the tabulation of such statistics when it compiled and issued ,block ,signal ,statistics as of ,january #a1 #aijh4 ,after this board went out of existence1 the ,bureau of ,safety of the ,interstate ,commerce ,commission continued the collection and publication of these data yearly4 ,perhaps no better word picture can be given of what ,dr4 ,robinson's invention has meant to the railroads than to present the story in the form of a table showing the miles of road and the track equipped with the track circuit since ,january #a1 #aijh4 ,in addition to the table1 the accompanying chart presents the information in a graphical form4 ,illustration3 ,progress ,chart of ,automatic ,signal ,installations ,since ,january #a1 #aijh4 ,track ,circuit ,mileage for ,automatic and ,controlled ,manual ,signals in the ,united ,states as ,taken from ,i4,c4,c4 ,reports ---------------------------------------- ---------------------------- ,automatic ,controlled ,manual ---------------------------------------- ---------------- ,miles of ,road ,miles of ,track ,miles ,miles ------------------------------------ of of ,track ,continuous ,track ,continuous ,road ,track ,circuits ,track ,circuits ,track at ,circuits at ,circuits ,station ,station ---------------------------------------- ------------------------ ,january #a1 #aijh #aj1hai4c #ah1ecd4a #gbf4g #bab4j #baah4j #daj4h #aiji #ab1agd4c #bj1eij4i #djg4f #egb4b #igh4j #adac4j #aiaj #ad1bch4i #bc1gga4c #che4h #dia4e #iec4e #acga4c #aiaa #ag1gji4h #bi1aea4f #dhc4i #dci4d #aaai4c #gci4i #aiab #bj1cjj4j #cc1cdc4h #djb4j #bie4i #iee4f #dif4j #aiac #bb1aif4f #cf1hgc4j #cgj4b #bbh4c #hfh4i #chj4c #aiad #bf1efi4c #dd1dfa4b #bge4g #ahj4c #fbe4c #bha4f #aiae #bi1hfc4e #di1ddb4a #bej4e #ade4a #edi4c #ahe4g #aiaf #cj1idb4e #ea1aai4g #bee4a #abe4a #edi4f #agi4c #aiag #cb1ied4f #ec1gii4h #bcj4c #acb4j #ebd4h #aee4e #aiah #ce1aic4a #eg1jhc4f #bjh4a #aca4b #dea4f #aed4h #aiai #cf1ihi4d #ei1deh4b #bba4b #bef4i #dhc4h #dda4b #aibj #cg1ifh4h #fj1iib4c #aif4c #abi4b #dac4c #aea4d #aiba #ch1edc4i #fa1gdd4e #bjf4h #abe4g #dbb4f #aff4d ---------------------------------------- ------------------------ ,the first yearly report of the ,bureau of ,safety1 ,i4,c4,c41 on block signals to contain information as to the miles of road and miles of track on which alternating current track circuits were installed1 was that issued as of ,january #a1 #aiad4 ,data taken from that report up to the last one issued is presented in the table below4 ,alternating ,current ,track ,circuit ,mileage ---------------------------------------- ------- ,miles of ,road ,miles of ,track ---------------------------------------- ------- ,january #a1 #aiad #c1bhi4b #d1add4f ,january #a1 #aiae #b1gbh4b #e1had4i ,january #a1 #aiaf #c1ahf4g #f1fgi4j ,january #a1 #aiag #c1ccf4b #f1hbc4f ,january #a1 #aiah #c1gdh4j #g1ecj4a ,january #a1 #aiai #d1dif4f #h1fbj4b ,january #a1 #aibj #d1fgf4e #i1jbf4j ,january #a1 #aiba #d1ghf4a #i1abj4b ---------------------------------------- ------- ,alternating current track circuits have certain advantages over direct current track circuits1 particularly in respect to their immunity to the dangerous effects of foreign direct current to which d4c4 track circuits in some communities are subjected4 ,the above table is therefore of interest as it shows the application of alternating current as made to ,dr4 ,robinson's invention of the closed track circuit4 ,part ,,iv ,,the ,,track ,,circuit ,,in ,,great ,,britain ,,and ,,on ,,the ,,continent ,by ,t4 ,s4 ,lascelles ,no satisfactory records appear to have been kept as to the origin and development of track circuiting outside the ,united ,states1 which renders it very difficult to arrive at any conclusions that could serve as a basis for a real historical sketch upon this interesting subject4 ,in view of the fact that the ,signal ,section of the ,american ,railway ,association proposes to publish a memorial to the late ,dr4 ,william ,robinson1 generally regarded as the inventor of the closed track circuit and certainly the first to utilize it in the control of an automatic block system1 the following brief remarks may prove of interest to the writer's fellow members of the ,signal ,section4 ,it is not suggested that they are in any sense complete1 as to make a complete survey would require considerable investigation4 ,they really represent the writer's present general understanding of the subject and are open to such criticism and correction as anyone may be able to offer to them1 in ,england or elsewhere4 ,there is no doubt but that track circuits were thought of and actually experimented with in ,england a great many years ago--probably as far back as the earliest ,american attempts--but the want of satisfactory records make it very difficult to decide on what actually took place4 ,however1 it is certain that the late ,w4 ,r4 ,sykes1 well-known throughout the railway world for his controlled manual block and other inventions1 endeavored to use the track circuit in the sixties and that ,bull1 the inventor of the bull-headed rail employed in ,england for the chaired track universally found there1 clearly had the idea of a track circuit in his mind1 for he refers to it in a patent obtained in #ahfj4 ,it was apparently in the early part of the sixties that ,w4 ,r4 ,sykes fixed a track circuit experimentally at ,briseton on the old ,london1 ,chatham and ,dover ,railway1 and shortly after also at the ,crystal ,palace ,station on the same line4 ,the apparatus employed must necessarily have been rather primitive4 ,in the seventies1 track circuit was installed by him at ,st4 ,paul's station1 also on the ,chatham ,railway4 ,at that time very little was known about the track circuit theoretically and the construction of the relay was very different from our modern types4 ,sykes' relay completed the control circuit by the insertion of a contact point into a mercury trough4 ,it was also1 the writer believes1 built on the solenoid principle4 ,so far as is known it was not suggested at this time and at all events not attempted to make an automatic block system controlled by track circuits1 such schemes for signaling of this type as were put forward being always based on the intermittent or track instrument control plan4 ,it must be remembered that the conditions obtaining in ,england1 widely different from those seen in the ,united ,states1 were not such as to give much encouragement to the development of automatic signaling1 while over and above this1 the ,english conservative nature always looked askance at automaticity in railway apparatus4 ,automatic signals1 worked on a track instrument plan1 were put into regular work on the ,liverpool ,overhead ,railway in #ahic1 but it was not till #aijb that automatic signals controlled by continuous closed track circuits were to be seen in operation on an ,english main line railway4 ,before this1 however1 track circuits had made some progress1 though not very much2 the most important instance of its application was in the ,kings ,cross tunnels1 just outside the ,london terminal of the ,great ,northern ,railway1 in the early nineties4 ,this installation1 which was used under none too favorable circumstances from the point of view of successful operation1 proved to the ,english what the track circuit could do and heralded the day when its place in the safe working of railways should be better appreciated4 ,by this time in the ,united ,states1 largely under the influence of the pioneer work of ,dr4 ,robinson1 automatic signaling had made quite considerable progress and the potentialities of the track circuit had been fairly realized4 ,it may occur to ,americans to ask why it was that progress in ,england was so slow and this is a question which cannot be answered by a single reason since a combination of circumstances was the cause4 ,in the first place the older type of ,english signal officer was extraordinarily conservative regarding signaling practice of other countries as he had that peculiar type of contempt which generally comes from want of knowledge4 ,anyone who1 like the writer1 listened for instance to the objections brought forward by some of these men to controlled manual block1 will know to what absurd lengths they could go in resisting improvements in working4 ,although this spirit1 which has markedly diminished during the last #ae years1 must have accounted to some extent for the slow development of the track circuit in ,england1 there were yet some reasons of a more sensible kind which must be borne in mind4 ,the ,english light weight four-wheeled freight car without air brakes was and still is a bother to the track circuit engineer because of the difficulty of getting a satisfactorily low shunt under all circumstances4 ,then again the ,mansell disc wheel made it necessary to resort to bonding between the tire and the hub before a vehicle would shunt the track circuit at all and this was an expense to which the companies were loath to go1 especially if they had or contemplated very few track circuits1 though the use of even one circuit really necessitated the whole of these wheels being so treated4 ,there was no great demand for automatic signaling1 as the manual system was giving good results and was also cheap at that time1 owing to the low wages paid to railway men4 ,this and the other reasons just given combined to render the progress in ,england extremely slow4 ,some of the ,first ,installations ,nevertheless1 in #aijb the ,british ,pneumatic ,railway ,signal ,company1 who had in the previous year installed its first low pressure pneumatic interlocking at ,grateley1 on the ,london and ,south ,western ,railway1 brought into use between that station and ,andover an automatic block system controlled by continuous track circuits1 the distance being about six miles4 ,the signals were worked by low pressure air4 ,the success of these systems led to the adoption of them shortly afterwards on the widened four-track main line between ,woking and ,basingstoke on the ,south ,western1 a distance of #bd miles4 ,the ,grateley-,andover installation has now been removed1 not because it was at all unsatisfactory1 but because it was felt traffic and other circumstances did not warrant its further employment4 ,in #aije1 ,hall electro-gas automatic signals were brought into use on the ,north ,eastern main line between ,alne and ,thirsk1 a distance of #aa miles4 ,in #aijg1 semi-automatic signals were installed between ,pangbourne and ,goring1 a distance of #b-c_/d miles1 four track1 by the ,great ,western ,railway to divide up a long manual block section and a few similar installations have been made on the ,midland1 the ,great ,central1 the ,belfast and ,county ,down and other roads4 ,by this year1 track circuiting had begun to be extensively used in ,england4 ,the ,british ,pneumatic ,signal ,company had installed a series of low-pressure plants near ,manchester on the ,great ,central and track circuits were used throughout while the same thing had been done at ,clapham ,junction on the ,south ,western4 ,the ,westinghouse ,company had supplied the ,district ,railway1 ,london1 with automatic signals and were actively engaged in fitting similar apparatus to the tube lines2 they soon afterwards commenced work on the ,metropolitan ,railway4 ,the main steam lines began to apply track circuits at various places in conjunction with ordinary manual signaling and this process received an added impetus from the terrible disaster which befell the ,midland ,company's ,scotch ,express near a station called ,hawes ,junction1 when1 in emerging from a tunnel it crashed into two light engines that had been forgotten and had entered the block under the signals set for the express4 ,several other bad accidents1 notably one at ,pontypridd1 on the ,taff ,vale ,railway1 due to trains and engines being overlooked by signalmen while standing at adverse signals1 emphasized the necessity for paying serious attention to the question of track circuiting and for undertaking a really earnest study of the matter to see whether the difficulties due to the light freight car1 etc41 could not be overcome or at least considerably minimized4 ,considerable progress had been made by the time the war broke out and quite a number of track circuits had come into existence on all the principal roads1 although no extension work worth noticing was made to purely automatic block systems on steam roads1 this class of work being confined to the suburban electric lines4 ,unfortunately1 in this as in so many things the war had a retarding effect and caused the postponement of many plans4 ,the increased price of wages and materials has hampered progress a great deal and it will be some time yet before any great improvement is noticeable4 ,on the other hand1 the great increase in wages has caused a demand on the railways for a reduction of operating costs with the result that signal engineers are endeavoring to produce schemes which will enable signal towers to be abolished or closed at intervals where they were formerly kept continuously in service and in this and other ways to dispense with unnecessary staff4 ,it is in this that the track circuit will help very considerably4 ,its further extension on ,english lines is a certainty and simply a question of time and money4 ,since the inception of the ,institution of ,railway ,signal ,engineers a great amount of work has been done in discussing and studying requisites and so on for track circuit work1 both of the direct current and alternating current types4 ,all this has resulted in increased confidence on the part of the traffic officers in track circuit and allied apparatus and caused them to look more and more to the signal engineer to help them in their work and to accord him the respect and credit he deserves4 ,the writer is aware that these lines can only convey a very imperfect idea of the actual state of affairs1 but he prefers to write them now as a preliminary account1 not yet being in a position to furnish the figures which the ,signal ,section desires4 ,track ,circuits on the ,continent ,turning to the continent1 the writer must necessarily speak in very general terms since there is less published on this subject by continental journals than by ,english and1 of course1 the field is rather a wide one1 embracing so many lands and tongues4 ,the track circuit is1 of course1 known there fairly well1 but there are no very great installations of automatic block to be found4 ,in the case of ,france1 the ,paris1 ,lyons ,mediterranean had1 before the war1 an installation between ,larsche and ,auperre1 #bd miles1 and some semi-automatic sections in various places4 ,the ,midi ,railway had also the ,hall disc system from ,bordeaux to ,langon1 #bf miles1 and the writer believes extensions to this have since been made4 ,the ,est ,railway began trials before the war and during the war1 owing to shortage of staff and having greatness of traffic to the eastern military area1 installed automatic signaling on the ,paris-,nugent line4 ,the writer has been told that it is under consideration to equip the whole line to ,avricourt1 where it connects with the ,alsace-,lorraine system4 ,the writer is not aware whether the other companies in ,france have any automatic blocks1 but he believes not4 ,they all have1 however1 track circuits installed at various places in connection with the ordinary signaling4 ,owing to the lower standard of living and the employment of women operators at many points1 there is not so great an incentive to the adoption of automatic devices1 as in some other countries4 ,french engineers1 however1 know what ,americans have done in this way and some very complete accounts of ,american systems have appeared in ,la ,revue generale des chemins de fer4 ,the ,paris ,metropolitan line is automatically signaled by an intermittent contact system without track circuit4 ,in ,germany1 the track circuit for steam lines is not looked on with much favor1 as owing to the extensive employment of the ,siemen's controlled manual and the peculiar station masters' system of control1 called ,station ,block1 always used in that country 7with1 it must be admitted1 a very high record for safety17 the ,germans think they would not gain much by any great use of track circuit or automatic signals4 ,the writer has just had this view confirmed by a friend returned from visiting the important works of the ,german ,railway ,signal ,company at ,bruchsal1 ,baden4 ,automatic signaling is used on certain important sections of the ,berlin ,elevated and ,underground ,road1 installed before the war by the ,westinghouse ,company1 of ,london1 with a4c4 double rail track circuits and this will be extended eventually to cover the remaining sections still worked by the ,siemen's controlled manual4 ,dr4 ,kemmann1 a member of the ,general ,railway ,direction1 ,berlin1 published last year a very interesting book describing his work with accounts also of the ,london ,underground and ,new ,york ,subway installations1 showing that foreign systems are studied in ,germany4 ,but for steam roads the writer believes from what he has studied of ,german methods and ideas on the subject that the manual system will remain in use and that the track circuit will not be much adopted4 ,the same remarks apply generally to ,austria1 ,holland and ,scandinavia1 though in the latter case ,english ideas are more in evidence and it is probable that the track circuit1 already in use to some extent1 will be developed as time goes on4 ,in ,austria automatic signaling was certainly tried on a small scale on the ,southern ,railway1 but with what results the writer cannot say4 ,in ,switzerland the extended use of iron ties is against the track circuit4 ,in ,belgium the ,hall system was at one time in use between ,ghent and ,wondelgem1 but as the course of the line was changed1 these signals were removed4 ,the section was about #c-a_/d miles long4 ,automatic signals do not exist there now but the track circuit is used at certain stations1 notably throughout the all-electric power installation at and close to ,brussles ,nord4 ,the writer does not believe it likely that automatic signaling will be used on the steam roads in ,belgium1 at all events for some time yet4 ,with regard to ,italy1 ,spain and ,portugal1 the writer does not possess details1 but believes it likely that the track circuit is only in use1 if at all1 at a few important stations4 ,the new ,metropolitan line in ,madrid is equipped with an intermittent contact system1 probably copied from the ,paris ,metropolitan4 ,although a little outside the scope of these notes1 the writer would emphasize that in the ,english colonies and in ,south ,america 7especially1 however1 the former7 the track circuit is being much used and its value appreciated4 ,automatic signaling is in use in ,victoria1 ,queensland1 ,south ,australia and ,new ,south ,wales4 ,the operating conditions in these countries no doubt much resemble ,american circumstances and the adoption of automatic signals is a natural development4 ,summing up1 the writer would say1 that the earliest experiments of ,w4 ,r4 ,sykes in ,england are probably as old as those of ,dr4 ,robinson1 but owing to the different circumstances in which the former inventor was placed1 he had little encouragement to continue them and thus ,american development at first went on far ahead of ,english1 while owing to the vastness of the ,american continent it must always present a larger field to the signal engineers' ingenuity and activity4 ,in later years1 however1 the ,english signalmen awoke to the importance of the question and installations were constructed which1 if smaller1 showed as great a degree of technical perfection as any in ,america4 ,the future will doubtless see more such installations4 ,it is not known to the writer whether anyone on the continent had the idea of a track circuit as far back as ,sykes' or ,robinson's experiments or when the first attempts were made4 ,it would require much investigation to find this out4 ,track circuit possibilities are now well known there and no doubt its use will extend1 but in certain countries1 notably ,germany and ,switzerland1 there are local circumstances which act rather strongly against it at present4 ,the writer cannot give statistics on the subject now4 ,there are some figures which he possesses1 but they should be verified and amplified before being used by the ,signal ,section for publication4 ,the preceding notes are1 he is too fully aware1 very incomplete and general1 but he hopes they may be of some present use4