,,american ,,society ,,of ,,civil       
,,engineers  ,,instituted #aheb         
,,transactions  ,paper ,no4 #aaeb       
,,the ,,new ,,york ,,tunnel ,,extension 
,,of ,,the ,,pennsylvania ,,railroad4   
,,the ,,east ,,river ,,division4  ,,by  
,,alfred ,,noble1 ,,past-,,president1   
,,am4 ,,soc4 ,c4 ,e4     ,a general     
outline of the work included in this    
,division has been given by ,general ,c4
 ,w4 ,raymond1 ,m4 ,am4 ,soc4 ,c4 ,e41  
in the first paper of the series4 ,the  
few pages following are intended only as
 a note to connect his paper with the   
more detailed descriptions of the       
execution of the work1 which will be    
supplied by the ,resident ,engineers in 
immediate charge4  ,soon after the      
,company's project was made public1 in  
the latter part of #aija1 borings were  
begun in the ,east ,river1 and a few    
weeks later in ,manhattan and ,long     
,island ,city4 ,a preliminary base line 
was measured on the ,manhattan side1 and
 temporary transit stations were        

established on buildings from which all 
borings in the river were located4 ,the 
river borings were all wash-borings made
 from a pile-driver boat4 ,after the    
results were plotted on the map1 contour
 lines were drawn to indicate the rock  
surface1 and profiles along the tunnel  
lines were plotted from the contours2 as
 the borings were preliminary to the    
final location of the tunnels1 and in   
many cases at some distance from the    
tunnel lines1 considerable divergence   
from the actual rock surface was        
expected1 and realized in a few places1 
yet on the whole the agreement was very 
good4 ,the borings revealed two         
depressions or channels where the rock  
surface passed below the grade of the   
projected tunnels1 these depressions    
being separated by a rock reef which    
extends down stream from ,blackwell's   
,island4 ,in #cb;d and #cc;d ,streets in
 ,manhattan1 borings were made from the 
river to the station site at intervals  
of about #ajj ft41 wash-borings and     

core-borings alternating4 ,in ,long     
,island ,city1 where the tunnel lines   
were to pass diagonally under the       
passenger station building and passenger
 yard of the ,long ,island ,railroad and
 under streets and private property1 the
 arrangement of borings was less        
regular1 although the alternation of    
wash-borings and core-borings was       
carried out as far as practicable4      
,after the final location of the work1  
additional borings were made1           
particularly on shaft sites and also    
along the approaches and in the         
,sunnyside ,yard1 ,long ,island ,city4  
,a triangulation was carried across the 
river with a measured base on each side4
 ,it was impossible to measure directly 
between the extremities of either base4 
,the bases were measured with #ajj-;ft4 
steel tapes1 supported every #bj ft41   
stretched with a uniform pull1 and      
frequently compared with standardized   
tapes4 ,on account of the crowded       
condition of the streets during the     

hours of daylight and evening1 most of  
the work was done between #aj ,p4 ,m4   
and #e ,a4 ,m4 ,similar measurements    
were made in the streets along the      
tunnel lines4 ,angle readings were      
repeated many times1 as is usual in such
 work4 ,fig4 #a shows the triangulation1
 the street measurements being omitted4 
,levels were first transmitted across   
the river by simultaneous observations  
of the river surface2 then by several   
repetitions1 across ,blackwell's ,island
 and the narrow channels on each side1  
where the longest sights were about     
#aajj ft42 and1 finally1 by several     
lines through the tunnel of the ,east   
,river ,gas ,company at #gast ,street4  
,the franchise granted by the ,city of  
,new ,york provided for the sale to the 
,railroad ,company of the portions of   
#cb;d ,street between ,seventh and      
,eighth ,avenues1 and between ,eighth   
and ,ninth ,avenues4 ,later1 the        
,company acquired by purchase the       
portion of #cb;d ,street between ,ninth 

and ,tenth ,avenues4 ,the franchise     
granted sub-surface rights under streets
 around the station site to within #ai  
ft4 of the street surface under         
,seventh1 ,eighth1 and ,ninth ,avenues2 
to within #cj in4 of the street surface 
under #cast and #cc;d ,streets1 except  
that1 under the sidewalks opposite the  
station1 that is to say1 the south      
sidewalk in #cast ,street and the north 
sidewalk in #cc;d ,street1 the          
construction must be at least #e ft4    
below the street surface4 ,in carrying  
out the work1 full use of these rights  
was made under ,eighth ,avenue1 but only
 under such portions of ,seventh and    
,ninth ,avenues as were indispensable   
for access by trains to the station     
area4 ,it was not practicable to make   
full use of the rights granted under    
#cast and #cc;d ,streets without        
incurring great expense for supporting  
adjacent buildings or for injuries to   
them1 and1 after careful consideration1 
the arrangement shown in the plans was  

decided on1 making about #de of the     
sub-surface area under these streets    
available at track level4               
,illustration3 ,,fig4                   
#a4--,triangulation ,system ,east ,river
 ,tunnel  ,the work of the ,east ,river 
,division at this site embraced the     
excavation to the depth necessary for   
railroad tracks1 and the building of a  
retaining wall extending in #cast       
,street from the east side of ,ninth    
,avenue to the west side of ,seventh    
,avenue1 thence northward along ,seventh
 ,avenue for a distance of #aee4e ft42  
also a retaining wall in #cc;d ,street  
from the west side of ,seventh ,avenue  
to the east side of ,ninth ,avenue1 and 
thence southward along ,ninth ,avenue   
for a distance of #acf4c ft4 ,this work 
was placed under contract ,june #bast1  
#aijd1 with the ,new ,york ,contracting 
and ,trucking ,company1 and later       
assigned by that company to the ,new    
,york ,contracting                      
,company-,pennsylvania ,terminal1 and   

was carried out under the direction of  
,george ,c4 ,clarke1 ,m4 ,am4 ,soc4 ,c4 
,e41 as ,resident ,engineer1 by whom it 
will be described in detail4            
,illustration3 ,,plate ,,ix4--,map of   
,portion of ,manhattan ,island from     
#bc;d to #djth ,streets1 ,showing       
,former ,topography ,from ,map ,made by 
,gen4 ,egbert ,l4 ,viele in #ahfe  ,the 
station tracks leading eastward from the
 station will converge under ,seventh   
,avenue and for some distance farther   
east1 and pass into two three-track     
tunnels1 one under #cb;d ,street and the
 other under #cc;d ,street1 at the      
respective distances of #aib and #djb   
ft4 from ,seventh ,avenue4 ,a typical   
cross-section of the three-track tunnel 
is shown on ,plate ,,xii4 ,the          
converging sections were considered as  
easterly extensions of the station1 and 
were not included in the ,east ,river   
,division4 ,within a few hundred feet   
7,plate ,,xiv71 the tracks are reduced  
to two1 each passing into a single tube1

 the two tunnels under each street being
 formed in one excavation1 the distance 
between center lines of tunnels being   
#bj ft4 #d in4 ,this construction has   
been termed a twin tunnel1 and a typical
 cross-section is shown on ,plate ,,xii4
 ,the tunnels continue on tangents under
 the streets to ,second ,avenue where   
they curve to the left by #a #cj'       
curves1 passing under private property1 
gradually diverging and passing through 
shafts just east of ,first ,avenue4     
,about #cej ft4 west of the shaft1 the  
divergence of the two lines from each   
street becomes sufficient to leave a    
rock dividing wall between them1 and    
thence eastward each tunnel is formed in
 a separate excavation4 ,a typical      
cross-section of the two separated      
tunnels is shown on ,plate ,,xii4  ,it  
thus appears that eastward from the     
station the lines constitute a          
four-track railroad1 each track being in
 a separate tunnel2 for convenience of  
the work these lines were designated ,a1

 ,b1 ,c1 and ,d1 from north to south4   
,illustration3 ,,plate ,x4--,manhattan  
,shaft1 ,lines ,a and ,b  ,at an early  
date1 when the organization of the      
engineering staff was taken up1 ,charles
 ,l4 ,harrison1 ,m4 ,am4 ,soc4 ,c4 ,e41 
was appointed ,principal ,assistant     
,engineer4 ,he was directly in charge of
 all parts of the work1 and all         
,resident ,engineers reported to him4   
,george ,leighton1 ,m4 ,am4 ,soc4 ,c4   
,e41 was placed in charge as ,resident  
,engineer of the #cc;d ,street lines    
from the west end of the three-track    
tunnel to the shaft and also eastward   
from the shaft under ,east ,river4 ,as  
he was not then able to endure the      
effects of compressed air1 the work     
under the river was transferred to      
,james ,h4 ,brace1 ,m4 ,am4 ,soc4 ,c4   
,e41 as ,resident ,engineer4 ,before the
 completion of the land tunnels under   
#cc;d ,street1 ,mr4 ,leighton accepted  
more responsible employment elsewhere1  
and ,mr4 ,brace assumed charge of them  

also4 ,francis ,mason1 ,m4 ,am4 ,soc4   
,c4 ,e41 was in charge as ,resident     
,engineer of the #cb;d ,street lines    
during their entire construction1 and   
also of the tunnels extending these     
lines eastward from the ,first ,avenue  
shaft under the river4  ,the work just  
described as the #cb;d and #cc;d ,street
 lines1 terminating at the easterly end 
at the ,first ,avenue shafts1 was placed
 under contract on ,may #bith1 #aije1   
with the ,united ,engineering and       
,contracting ,company4 ,the plans then  
provided for three-track tunnels from   
the west end of the work under the      
contract eastward #a1fbh ft4 in #cb;d   
,street and #a1dah ft4 in #cc;d ,street 
to the west line of ,fifth ,avenue1 with
 a descending grade of #j4d2 this was to
 constitute1 in a degree1 an extension  
of the station1 where trains could stand
 without brakes while awaiting signals  
to proceed to or from the station4 ,from
 ,fifth ,avenue eastward to the lowest  
point under the river1 the grade was to 

be #a4e on all lines4 ,later1 during    
construction1 when excavating westward  
under #cc;d ,street from ,fifth ,avenue1
 the surface of the rock was broken     
through1 disclosing quicksand2 within   
the next few days trial drill holes     
through the tunnel roof at #cb;d ,street
 and ,fifth ,avenue showed a thin cover 
with quicksand above it4 ,the conditions
 had been indicated in a general way by 
borings made before construction was    
begun1 but they proved to be rather     
worse than anticipated4 ,on the         
topographical map of ,manhattan ,island1
 made by ,general ,egbert ,l4 ,viele in 
#ahfe1 is shown a watercourse which had 
its source near what is now ,broadway   
and #ddth ,street1 flowing thence along 
the west side and south end of ,murray  
,hill1 passing under the present site of
 the ,waldorf-,astoria ,hotel1 crossing 
#cc;d ,street at the point where the    
rock surface was broken through in the  
tunnel excavation1 as above stated1     
crossing #cb;d ,street at its           

intersection with ,fifth ,avenue1 where 
trial drilling showed thin rock cover   
over the tunnel excavation1 passing     
thence eastward a short distance south  
of #cb;d ,street1 which it recrossed    
near ,third ,avenue1 and finally        
discharging into the ,east ,river near  
#cdth ,street1 and a little west of the 
present ,first ,avenue4 ,the ancient    
creek apparently followed the course of 
a valley in the rock1 the valley having 
become filled to a considerable depth   
with very fine quicksand4 ,this         
concurrence of depressions in the rock  
surface with the watercourse shown on   
,viele's map was noted in so many places
 and the difficulties of construction   
were so serious at these places1 that a 
section of the map showing the old      
topography along and adjacent to the    
station and tunnel lines is reproduced  
in ,plate ,,ix4  ,illustration3 ,,plate 
,,xi4--,long ,island ,shaft4 ,lines ,a  
and ,b  ,the unfavorable conditions     
developed at ,fifth ,avenue affected    

both the construction of the tunnels and
 the maintenance of adjacent buildings4 
,it would be necessary to construct the 
tunnels in open cut for a large part of 
the way westward1 causing serious       
inconvenience to the public2 the        
buildings were mostly of the older      
class1 founded in earth1 but there were 
several modern high buildings with      
foundations in the same material2 some  
of these had been built since the       
tunnels were planned4 ,in view of these 
added risks and the increased cost of   
construction1 the value of the          
three-track construction was            
reconsidered1 and two important changes 
were made in the plans4 ,the first of   
these was to continue the twin tunnel   
westward to ,sixth ,avenue in #cb;d     
,street1 and to a point #ahj ft4 west of
 ,sixth ,avenue in #cc;d ,street2 the   
twin tunnel being #i-a_/b ft4 less in   
height than the three-track tunnel and  
#i ft4 narrower1 the change reduced the 
difficulties considerably4 ,where the   

three-track tunnel was thus eliminated1 
there was no longer objection to a      
steeper grade1 so that1 going eastward  
from the station1 a grade of #j4h in    
#cc;d ,street and #j4i in #cb;d ,street 
was substituted for the original #j4d   
grade4 ,from the west line of ,fifth    
,avenue eastward short sections with    
descending grades of #j4c connect with  
the original #a4e grade near ,madison   
,avenue4 ,the effect of these two       
changes--type of tunnel and grade--was  
to lower the roof of the tunnels at     
,fifth ,avenue about #ae ft41 which made
 it practicable to avoid open cutting   
east of ,sixth ,avenue4  ,a full account
 of the construction of the cross-town  
tunnels will be given by the ,resident  
,engineers4  ,permanent shafts were made
 on both sides of the ,east ,river1     
those in ,manhattan being located a few 
feet east of ,first ,avenue1 and those  
in ,long ,island ,city being located1   
one in the so-called ,annex ,slip1 the  
other in the pier just south of it4 ,the

 two railroad lines coming from #cb;d   
,street in ,manhattan1 and curving to   
the left at ,second ,avenue1 are about  
#cd ft4 apart between centers at ,first 
,avenue1 and it was convenient to make  
the shaft large enough to cover both    
lines4 ,borings had shown that the      
excavation for the tunnels would break  
out of the rock about #bjj ft4 east of  
,first ,avenue4 ,it was desirable to    
carry the tunnel excavation eastward    
from the shaft in normal air far enough 
to permit of building at least #ej ft4  
of tunnel and installing air-locks1 so  
that compressed air might be available  
when the rock surface was broken        
through4 ,the location adopted1 and     
shown on ,plate ,,xiii1 had the further 
advantages that the rock surface was    
several feet above the level of the top 
of the tunnels1 and access to the river 
for receiving and discharging materials 
could be had without crossing any       
street4 ,similar reasons governed the   
location of the north shaft for the     

lines from #cc;d ,street4 ,on the ,long 
,island side of the river there were    
only two feasible locations meeting     
these conditions1 particularly in       
respect to a safe thickness of rock     
above the tunnels1 one near the pierhead
 line1 the other just outside the       
bulkhead line1 and for many minor       
reasons the latter was preferable4 ,the 
center lines of each pair of tunnels    
were #cg ft4 apart1 and each shaft1     
therefore1 was made to cross both lines 
of a pair1 the same as on ,manhattan    
side of the river4 ,it was not expected1
 however1 that the ,long ,island shafts 
could be built conveniently or the      
tunnels begun from them in normal air4  
,the decision to make the shafts of     
permanent construction was based not    
only on the desirability of having      
access to and egress from the tunnels   
near the banks of the river for         
convenience of the workmen or exit for  
passengers in case of accident1 but to  
facilitate ventilation2 these locations 

divide the entire lengths of tunnels    
east of the station into three parts1   
two of which were approximately #d1jjj  
ft4 each1 and the other about #e1ejj ft4
 ,the accident risk was believed to be  
very small1 while much weight was given 
to the feature of facilitating          
ventilation4 ,further studies have      
enhanced the importance attached to     
ventilation1 and it is now intended to  
provide appliances for mechanical       
ventilation at all shafts4 ,the plans of
 the shafts are shown on ,plates ,x and 
,,xi4 ,the caissons for the shafts are  
of structural steel1 with double walls1 
filled between with concrete1 including 
a cross-wall between and parallel to the
 tunnels4 ,all these structures were    
fitted for sinking with compressed air1 
if that should prove necessary4         
,although borings had shown that rock   
would be found at all the shaft sites   
several feet above the tunnel level1 it 
could not be determined in advance of   
excavation whether the caissons would   

have to be sunk to full depth2 if sound1
 unfissured rock were found1 the sinking
 could be stopped above the tunnel      
level2 but1 if not1 the caissons1 in any
 case1 would have to be sunk far enough 
to permit placing a water-tight floor   
below the tunnels1 and the tunnels      
themselves begun through openings in the
 side-walls of the caisson2 such        
openings1 therefore1 closed by removable
 bulkheads1 were provided in all        
caissons4  ,illustration3 ,,plate       
,,xii4--,typical ,tunnel ,sections  ,as 
already stated1 the grade of #a4e from  
,fifth ,avenue eastward was fixed with  
reference to the lowest point of the    
river bed in order to give the requisite
 cover over the tunnels at the deepest  
point of the channel on the west side of
 the reef1 where the river bottom was   
about #fj ft4 below mean high tide for a
 short distance4 ,on the other hand1 as 
the use of compressed air in building   
the tunnels was anticipated1 an         
excessive depth below the water surface 

was to be avoided as far as possible2 it
 was necessary1 however1 to continue the
 descending grade some further distance 
until the tunnels were mostly in rock1  
so that drainage sumps under the tunnels
 could be made readily4 ,eastward from  
the sumps the tunnels had a rising grade
 of #j4g to the established bulkhead    
line on the ,long ,island side1 giving a
 cover at the points where the tunnels  
enter rock1 a short distance westward1  
of about #aj ft4 7if the dredging plane 
should be fixed at some future time at  
#dj ft4 below mean low tide1 as may be  
reasonably anticipated74 ,eastward from 
the bulkhead line1 ,tunnels ,a1 ,b1 and 
,d have ascending grades of about #a4be1
 while ,tunnel ,c rises at the rate of  
#a4i in order to effect a crossing over 
,tunnel ,b west of the portals4 ,this   
feature was introduced in order to place
 the two west-bound tracks together     
through the ,sunnyside ,yard1 and the   
heavier grade1 being downward with the  
traffic1 was not objectionable4  ,the   

arrangement of grades and tracks in the 
approaches and in ,sunnyside ,yard would
 require the introduction of too much   
detail to be taken up here1 but will be 
dealt with in the paper on the          
,sunnyside ,yard4  ,it was recognized   
from the inception of the project that  
the tunnels under the ,east ,river would
 be the most difficult and expensive    
section of the ,east ,river ,division4  
,the borings had shown a great variety  
of materials to be passed through1      
embracing quicksand1 coarse sand1       
gravel1 boulders1 and bed-rock1 as well 
as some clayey materials4 7,see ,plate  
,,xiii47 ,the rock was usually covered  
by a few feet of sand1 gravel1 and      
boulders intermixed1 but1 in some       
places1 where the rock surface was at   
some distance below the tunnel grade1   
the material met in tunneling was all   
quicksand2 the nearest parallels in work
 previously done were some of the       
tunnels under the ,thames1 particularly 
the ,blackwall tunnel1 where open gravel

 was passed through4 ,before the plans  
for the ,east ,river tunnels were       
completed1 work had been resumed1 after 
many years' interruption1 in the old    
,hudson ,river tunnels between #aeth    
,street1 ,jersey ,city1 and ,morton     
,street1 ,manhattan1 and sand materials 
were passed through for a short         
distance4 ,these experiences satisfied  
nearly all the engineers in any way     
connected with the work that the shield 
method was the most suitable for the    
,east ,river tunnels1 and the plans for 
the work were based on its adoption4    
7,see ,plate ,,xii for cross-sections1  
etc47 ,other methods1 as stated by      
,general ,raymond in the introductory   
paper1 were advocated1 particularly     
caisson constructions and the freezing  
process1 the latter being urged very    
strongly1 and1 when proposals were      
invited1 in ,october1 #aijc1 bidders    
were informed that alternative methods  
would be taken into consideration4      
,bids were received and opened on       

,december #aeth1 #aijc4 ,only one bidder
 proposed to carry out the work on the  
basis of unit prices1 but the prices    
were so low that the acceptance of the  
proposal was deemed inadmissible2 no bid
 based on caisson methods was received2 
several offers were made to perform the 
work by the shield method1 in accordance
 with the plans1 for a percentage of its
 cost1 and one was submitted1 on a      
similar basis1 covering the use of the  
freezing method4 ,the firm of ,s4       
,pearson and ,son1 ,limited1 of ,london1
 ,england1 submitted a proposal for     
building the tunnels by the shield      
method1 on a modification of the        
percentage basis1 and as this firm had  
built the ,blackwall tunnel within the  
estimates of cost and was the only      
bidder having such an experience and    
record in work in any way similar to the
 ,east ,river tunnels1 negotiations were
 continued between that firm and the    
railroad company4  ,the original plans  
and specifications contemplated that all

 tunnels between the ,first ,avenue     
shafts in ,manhattan and ,east ,avenue  
in ,long ,island ,city would be         
shield-driven1 and that work would      
proceed simultaneously eastward from the
 ,first ,avenue shafts and both eastward
 and westward from the ,long ,island    
,city shafts located west of ,front     
,street at the river1 requiring twelve  
shields4 ,when making their proposal1   
,s4 ,pearson and ,son1 ,limited1        
suggested that shields might be started 
from the east end of the work and arrive
 at the ,front ,street shafts as soon as
 these shafts could be completed1 and   
proposed sinking a temporary shaft      
transversely across all four lines near 
the east end of the work just west of   
,east ,avenue1 from which1 within a     
short time1 to drive toward ,front      
,street by the use of shields4 ,the     
railroad company accepted the suggestion
 for the additional shaft1 although the 
greater part of the tunnels east of     
,front ,street was built without        

shields4 ,after several months of       
negotiation1 a contract was entered into
 on ,july #gth1 #aijd1 with ,s4 ,pearson
 and ,son1 ,incorporated1 a corporation 
of the ,state of ,new ,york organized by
 the ,english firm for the purpose of   
entering into and carrying out this     
contract4 ,the main features had been   
agreed upon1 and work had begun about   
two months before4 ,the contract        
embraced the permanent shafts in        
,manhattan and ,long ,island ,city1 the 
tunnels between these shafts1 and their 
extension eastward in ,long ,island     
,city to ,east ,avenue1 including in all
 about #bc1fjj ft4 of single-track      
tunnels4 ,the contract had novel        
features1 and seemed to be peculiarly   
suitable for the unknown risks and the  
unusual magnitude of the work4 ,a fixed 
amount was named as contractor's profit4
 ,if the actual cost of the work when   
completed1 including this sum named as  
contractor's profit1 should be less than
 a certain estimated amount named in the

 contract1 the contractor should have   
one-half of the saving4 ,if1 on the     
other hand1 the actual cost of the      
completed work1 including the fixed sum 
for contractor's profit1 should exceed  
the estimated cost named in the         
contract1 the contractor should pay     
one-half the excess and the railroad    
company the other half2 the contractor's
 liability was limited1 however1 to the 
amount named for profit plus #a1jjj1jjj2
 or1 in other words1 his maximum money  
loss would be #a1jjj1jjj4 ,any further  
excess of cost was to be borne wholly by
 the railroad company4 ,the management  
of the work1 with some unimportant      
restrictions1 was placed with the       
contractor2 the relations of the        
engineer1 as to plans1 inspection1 etc41
 were the same as in ordinary work1 and 
the interest of the contractor to reduce
 cost was the same in kind as in        
ordinary work4  ,illustration3 ,,plate  
,,xiii4--,plan and ,profile4 ,east      
,river ,tunnels  ,on account of the     

extent of the work embraced in this     
contract1 and the dangerous exposure to 
compressed air required in most of it1  
it was divided into three residencies2  
two of these1 including also the        
cross-town tunnels1 have been described2
 the third1 with ,s4 ,h4 ,woodard1 ,m4  
,am4 ,soc4 ,c4 ,e41 as ,resident        
,engineer1 embraced all tunnels from the
 easterly end of the work near ,east    
,avenue in ,long ,island ,city to the   
meeting points under the river and also 
the permanent shafts in ,long ,island   
,city4 ,a few months after the execution
 of the principal contract1 the work to 
be done was extended eastward #ajg4e    
ft41 across ,east ,avenue4 ,the         
extensions of the tunnels were built    
without cast-iron linings and with an   
interior cross-section of the same      
height as the tube tunnels1 but somewhat
 narrower4 ,the work was also extended  
westward from the ,first ,avenue shafts 
to include the excavation of top        
headings in each tunnel for a distance  

of #ajj ft4 and an enlargement to full  
size for #ej ft4 ,the borings having    
shown that soft earth existed below the 
grade of the tops of the tunnel under   
the passenger station building of the   
,long ,island ,railroad on the east side
 of ,front ,street1 and that earth of   
varying character would be met in places
 beyond the station building under the  
railroad tracks in the passenger yard   
and the street car tracks in ,borden    
,avenue1 it had been decided1 before    
proposals were invited1 to extend the   
metal lining eastward to ,east ,avenue1 
at the east end of the work embraced in 
the original contract1 where the rising 
tunnel grades approached the surface of 
the ground so closely that their further
 extension would be in open cut4 ,in    
places where the tunnels were wholly in 
rock1 the weight of the cast-iron tunnel
 lining was reduced #dc2 where the      
surface of the rock was below the top of
 the tunnel1 but above the axis1 the    
reduction of weight was somewhat less1  

about #be2 notwithstanding these        
savings1 the cost of the tunnels was    
probably increased by the use of the    
cast-iron lining2 on the other hand1    
when passing through bad ground1 a      
section of tunnel could be made         
absolutely safe more quickly by erecting
 the lining as soon as a length of a few
 feet of tunnel was ready2 under a      
crowded passenger yard1 this feature had
 great value4  ,the execution of the    
work under this contract will be        
described fully by the ,resident        
,engineers4  ,the plant assembled by the
 contractors is believed to be the most 
extensive ever placed on a single piece 
of work1 and will be described in detail
 by their ,managing ,engineer1 ,henry   
,japp1 ,m4 ,am4 ,soc4 ,c4 ,e4  ,for     
convenience in receiving materials to be
 used in construction1 and to facilitate
 the disposal of excavated materials1   
one pier was leased on the east side of 
the ,hudson ,river1 two on the west side
 of the ,east ,river and three on the   

east side4 ,excavated materials from the
 station1 the cross-town tunnels1 and   
the river tunnels1 were placed on barges
 furnished by ,mr4 ,henry ,steers under 
several contracts embracing also the    
disposal of the materials4 ,in the      
earlier part of the work1 they were used
 as fill in the freight terminal of the 
,pennsylvania ,railroad at ,greenville  
on the west side of the ,upper ,bay2    
when the fill at this place was         
completed1 the materials were sent to   
the tunnel company's yard on the        
,passaic1 at ,harrison1 ,n4 ,j41 and a  
small part to the embankment in the     
,meadows ,division4 ,on account of the  
occasional closing of the ,passaic by   
ice1 this involved the possibility of1  
and to some extent resulted in1         
interruptions to the work of excavation4
 ,the contract for the cross-town       
tunnels carried an option in favor of   
the company to require the contractor   
for those tunnels to dispose of         
materials at a stated price1 and in the 

latter part of #aijg1 when the          
excavation in these tunnels was being   
pushed rapidly1 the railroad company1   
unwilling to incur the responsibility   
for delays during the winter1 availed   
itself of this option4 ,the disposal of 
materials was an important part of the  
work1 and will be dealt with more fully 
by the ,resident ,engineers4            
,illustration3 ,,plate ,,xiv4--,map and 
,profile1 ,cross-,town ,tunnels  ,at the
 time the contract was made with ,s4    
,pearson and ,son1 ,incorporated1 it had
 not been determined whether mechanical 
ventilation would be provided for the   
tunnels1 and therefore the contract with
 that firm did not include the final    
concrete lining at the shafts1 above the
 inverts of the tunnels4 ,after the     
adoption of plans for mechanical        
ventilation1 in the latter part of      
#aijh1 the plans for lining the shafts  
with concrete1 including flues for      
conducting air to the tunnels1 and      
stairways for ingress and egress1 were  

completed1 and the work was placed under
 contract2 it will be described in      
detail by ,f4 ,m4 ,green1 ,assoc4 ,m4   
,am4 ,soc4 ,c4 ,e4  ,at the east end of 
the work under the ,pearson contract1   
the rising grade of the tunnels brought 
them so near the surface of the ground  
that their extension eastward could be  
carried out more readily in open cut    
than by tunneling4 ,the locations of the
 portals could be varied somewhat1 and  
they were built on rock which was found 
in rather narrow ridges at convenient   
places4 ,tunnels ,b and ,d have a common
 portal2 ,tunnels ,a and ,c have        
separate ones1 the portal for ,tunnel ,c
 being located about #hjj ft1 west of   
the others as a result of its crossing  
over ,tunnel ,b1 as already explained4  
,eastward from the portals1 the track   
system expands1 in order to provide     
connections with the tracks of the ,long
 ,island ,railroad to and from ,long    
,island ,city1 with the ,new ,york      
,connecting ,railroad and ,new ,england 

lines1 and with the storage and cleaning
 yard known as the ,sunnyside ,yard     
extending to the west side of ,woodside 
,avenue1 #b-c_/d miles east of the ,east
 ,river4 7,plate ,,xv47 ,the yard and   
approaches are designed to avoid grade  
crossings by opposing trains4 ,the      
various general features of the yard and
 tunnel approaches1 bridge crossings1   
and street closings1 have been described
 in sufficient detail by ,general       
,raymond in the introductory paper4     
,illustration3 ,,plate ,,xv4--,plan and 
,profile of ,lines ,a and ,b1 and       
,sunnyside ,yards  ,for convenience in  
placing the work under contract1 a line 
was drawn #aj ft4 west of ,thomson      
,avenue1 dividing the work east of that 
embraced in the ,pearson contract into  
two parts4 ,the work west of the line   
was placed under the immediate direction
 of ,george ,c4 ,clarke1 ,m4 ,am4 ,soc4 
,c4 ,e41 as ,resident ,engineer1 with   
,naughton ,company and ,arthur          
,mc,mullen1 ,contractors2 ,mr4 ,louis   

,h4 ,barker was ,resident ,engineer of  
the part east of the dividing line1 with
 the ,degnon ,realty and ,terminal      
,improvement ,company as the principal  
contractors4 ,the substructures of the  
several bridges in or across the yard   
were included in these contracts1 but   
the superstructures were carried out by 
various bridge companies1 and other     
minor features were executed by other   
contractors4 ,more complete descriptions
 of the plans and of the execution of   
the work will be given by the ,resident 
,engineers4