AMERICAN SOCIETY OF CIVIL ENGINEERS

INSTITUTED 1852

TRANSACTIONS

Paper No. 1151

THE NEW YORK TUNNEL EXTENSION OF THEPENNSYLVANIA RAILROAD. 

THE NORTH RIVER DIVISION. 

BY CHARLES M. JACOBS, M. AM. SOC. C. E. 

These observations are written with the purpose of outlining briefly, asfar as the writer was concerned, the evolution of the scheme of bringingthe Pennsylvania Railroad and the Long Island Railroad into New YorkCity, and also, as Chief Engineer of the North River Division of the NewYork Tunnel Extension of the Pennsylvania Railroad, to record in ageneral way some of the leading features of the work on this division, which is that portion of the work extending from the east line of NinthAvenue, New York City, to the Hackensack Portal on the westerly side ofthe Palisades, as an introduction to the papers by the Chief AssistantEngineer and the Resident Engineers describing in detail the work asconstructed. 

It may be stated that, since shortly after the year 1871, when thePennsylvania Railroad system was extended to New York Harbor through thelease of the New Jersey Lines, the officers of that company have beendesirous of reaching New York City by direct rail connection. 

The writer's first connection with the tunneling of the North River wasearly in 1890, when he was consulted by the late Austin Corbin, President of the Long Island Railroad Company and the Philadelphia andReading Railroad Company, as to the feasibility of connecting the LongIsland Railroad with the Philadelphia and Reading Railroad (or with theCentral Railroad of New Jersey, which was the New York connection of theReading) by a tunnel from the foot of Atlantic Avenue, Brooklyn, underthe Battery and New York City, and directly across the North River tothe terminal of the Central Railroad of New Jersey. Surveys, borings, and thorough investigations were made, and the Metropolitan UndergroundRailroad Company was incorporated in the State of New York to constructthis railroad. Mr. Corbin, however, was aware that, in thetransportation problem he had in hand, the Central Railroad of NewJersey and the Philadelphia and Reading Railroad were not as importantfactors as the Pennsylvania Railroad, and, in consequence, he abandonedthe scheme for a tunnel to the Central Railroad of New Jersey for a linedirect to the Pennsylvania Railroad terminal in Jersey City. 

Meantime, the Pennsylvania Railroad Company, as a result of itsinvestigation of the matter, in June, 1891, thought that the mostfeasible project seemed to be to build tunnels for rapid transitpassenger service from its Jersey City Station to the lower part of NewYork, connecting there with the rapid transit systems of that city, andalso extending under New York on the line of Cortlandt Street, withstations and passenger lifts at the main streets and elevated railroads. 

The late A. J. Cassatt, then a Director of the Pennsylvania RailroadCompany, and previous thereto as General Manager and Vice-President (andlater as President) of that company, was deeply interested in obtainingan entrance into New York City, but was not satisfied with the proposedrapid transit passenger tunnels which required the termination of thePennsylvania Railroad trains at its Jersey City Station. Therefore, uponhis request, in September of the same year, another study and report wasmade by Joseph T. Richards, M. Am. Soc. C. E. , then Engineer ofMaintenance of Way of the Pennsylvania Railroad, on a route beginning inNew York City at 38th Street and Park Avenue on the high ground ofMurray Hill, thence crossing the East River on a bridge, and passingaround Brooklyn to Bay Ridge, thence under the Lower Bay or Narrows toStaten Island and across to the mainland, reaching the New York Divisionof the Pennsylvania Railroad at some point between Rahway and Metuchen. Mr. Cassatt also had in mind at that time a connection with the NewEngland Railroad, then independent, but now part of the New York, NewHaven, and Hartford Railroad system, by means of the Long IslandRailroad, and a tunnel under the East River, which in later years, asthe result of further consideration of the situation, has been coveredby the proposed New York Connecting Railroad with a bridge across theEast River and over Ward's and Randall's Islands. 

As a result of these investigations, the late George D. Roberts, who wasthen President of the Pennsylvania Railroad Company, authorized anexpenditure of about $25, 000 for soundings to determine the nature ofthe strata for tunneling under water. These soundings were carefullymade by Mr. Richards with a diamond drill, bringing up the actual coreof all rock found in crossing the waters of New York Bay from the westto the east side and extending from the Narrows to the Jersey CityStation of the Pennsylvania Railroad. 

After these investigations had been made, early in 1892, Mr. Robertsexpressed himself as being favorable to the undertaking, with thedefinite limitation that the tunnels must be for small cars doing localsuburban business, and for the transfer of Pennsylvania Railroadpassengers to and from New York, Brooklyn, and Jersey City, and not inany way to be tunnels for standard steam equipment, the expense forterminals and the prohibited use of coal for fuel in such tunnels notwarranting any broader consideration. Under such instructions, theinterests of the Pennsylvania Railroad Company for effecting a physicalentrance into New York City in that year were turned over to Samuel Rea, M. Am. Soc. C. E. , then Assistant to the President of that Company, whohas been identified with the investigations, and the progress andconstruction of this work since that time, Mr. Cassatt also working inconjunction with him on the plans then and since considered by thePennsylvania Railroad Management. 

On October 5th, 1892, Mr. Rea, under special direction of PresidentRoberts, made an extended investigation of the various routes which hadthen been projected for extending the system into New York City by railor transport, and reported to Mr. Roberts that, in his opinion, becauseof the limitation of the tunnel scheme to rapid transit trains and theconsequent transfer of passengers and traffic carried in passengertrains, and because of the drawbacks caused by the use of steamlocomotives in full-sized tunnels, and the objection to cable tractionor any system of transportation which had not then stood the test ofyears of practical service, the plan of the North River Bridge forreaching New York City and establishing a terminus therein was the bestthat had been evolved up to that time. The plan provided a direct railentrance into New York City for all railroads reaching the west side ofthe Hudson River, and also for the New York Central and Hudson RiverRailroad, as well as adequate station facilities in that city. Thisbridge would have had one clear span of 3, 100 ft. Between pier heads, landing on the New York side at the foot of West 23d Street, and thencethe line would have passed diagonally to the terminus at Sixth Avenueand 25th Street. The location of the terminus was subsequently changedto the vicinity of Seventh Avenue and 36th Street. The bridge wasdesigned with three decks: The first or lower deck was to accommodateeight steam railroad tracks; the second was to have six tracks, four ofwhich could be assigned for rapid transit trains operating with electricpower, and the other two for steam railroad trains; the third deck, reached by elevators, was to be a promenade extending from anchorage toanchorage. A connection with the Eleventh Avenue tracks of the New YorkCentral and Hudson River Railroad was to bring the trains of that roadinto the Union Station. The Bridge Company had a Federalcharter--granted in 1888--with broad powers. Gustav Lindenthal, M. Am. Soc. C. E. , was Chief Engineer, and he and Mr. Rea were corporators andamong its early promoters. The Pennsylvania Railroad Management lookedwith favor on its construction at that time, as subaqueous tunnels, withstandard railroad equipment with steam traction, were not regarded as afinal or attractive solution of the problem, from the standpoint of theManagement, and at a subsequent period the Pennsylvania Railroad Companyagreed to use the North River Bridge provided the other roads reachingthe west bank of the Hudson River would join. These roads, however, didnot avail themselves of the opportunity which in its broadest scope waslaid before them in 1900, after the Board of Directors of thePennsylvania Railroad Company had approved the scheme at the instance ofMr. Cassatt. 

The scheme of Mr. Corbin for a subway connection, between FlatbushAvenue and the Jersey City Station of the Pennsylvania Railroad, forlocal transit, took form in 1892, and, jointly with the Pennsylvaniainterests, railroad companies were incorporated in the respective Statesto build a tunnel from under the Jersey City Station, under the HudsonRiver to Cortlandt Street, New York City, thence under Maiden Lane, theEast River, and Pineapple and Fulton Streets, Brooklyn, to a location ator near Flatbush and Atlantic Avenues. On May 9th, 1893, these companieswere merged into the Brooklyn, New York and Jersey City TerminalRailroad Company, and estimates and reports on the construction weremade ready by the writer in association with Mr. Rea, pendingapplication for the franchises. The panic of 1893, occurring about thattime, checked further progress on this scheme, and, before it could berevived again, other important projects for reaching New York City weregiven consideration. 

That part of Mr. Corbin's plan contemplating a subway under AtlanticAvenue in Brooklyn to the present Flatbush Avenue Terminal was not a newidea, as a tunnel had been built in 1845 and operated under a portion ofAtlantic Avenue, but later it was filled up. Plate IV, reproduced from acrayon sketch which was the property of the late William H. Baldwin, Jr. , is a view of this tunnel. 

In conjunction with schemes for river tunnels, complete plans for rapidtransit subways for New York City, very much on the line of the presentrapid transit subways, were also prepared for Mr. Corbin by the writer. These plans provided a system of deep tunnels in rock, entirely belowthe plane of quicksand, and at the Battery the lines were to connectdirectly into the tunnels to Long Island and New Jersey, respectively, and the stations throughout, where the rock was at a deep level, were tobe fitted with elevators, grouped as suggested in Plate V, using privateproperty on each side of the street at station locations--one side fornorth-bound and the other side for south-bound traffic. These plans weresubmitted to the first Rapid Transit Commission, and, after longconsideration, were rejected by that Commission because they providedfor the construction of the tunnels by a private company, notwithstanding Mr. Corbin gave the Commission assurances of amplefinancial means to carry the work to completion. 

During the years 1892-93 Mr. Corbin was convinced that it was necessaryto get better facilities for handling the baggage and express matter ofthe Long Island Railroad and the Long Island Express Company across theEast River between Long Island City and New York City, and heinstructed the writer to investigate and report on the feasibility ofbuilding a tunnel, along the lines of the East River Gas Tunnels, thennearly completed, between the foot of East 34th Street, New York City, and the Long Island City Station of the Long Island Railroad. In 1893 aninvestigation was made for such a tunnel, to be of similar size to theEast River Gas Tunnel (8 by 10 ft. ), solely for the purpose of handlingbaggage and express matter. Investigation was made and estimatesprepared, but the cost was considered to be prohibitive in view of thepossible earnings solely from the handling of baggage and express, andthe matter was not considered further. 

[Illustration: PLATE IV. --TUNNEL UNDER PART OF ATLANTIC AVENUE, BROOKLYN. 

(From a Crayon Sketch. )]

While Mr. Corbin was deeply interested in the down-town river tunnels, the up-town situation was of great importance to the Long IslandRailroad, and, having allied himself with Mr. Charles Pratt, they tookup generally the franchise owned by Dr. Thomas Rainey for a bridge overBlackwell's Island. Mr. Corbin became interested with Dr. Rainey in1894, and the actual construction proceeded on this bridge. The designprovided for four railroad tracks, besides highways for tracks, pedestrians, etc. , with a terminal station at Third Avenue and 64thStreet, New York City, which, under the franchise, was the limit towhich the railroad could proceed. 

At this period there were two projects for bridging the Hudson or NorthRiver: the New York and New Jersey Bridge Company at about 59th Street, and the North River Bridge Company at 23d Street, as hereinbeforedescribed. Several studies were made by the writer, with the idea ofmaking a rail connection between the Long Island "Rainey" bridge and abridge over the North River. An overhead structure connection wasprohibitory, as no franchise could be obtained to cross Fifth Avenuewith an overhead structure. Sketches were prepared for a subwayconstruction to connect with the bridges, but a final plan was notworked out. 

The failure to carry out the joint undertaking with the PennsylvaniaRailroad Company in 1893 led Mr. Corbin to revive the scheme ofextending the Long Island Railroad from Flatbush Avenue, Brooklyn, toNew York City, therefore consideration was given to a relocation of theroute for Mr. Corbin during the early months of 1896, the idea beingthat the entire up-town outlet for the Long Island Railroad would be byBlackwell's Island Bridge, and the tunnel project would give thedown-town outlet. 

At this time a commission had been appointed by the Legislature toinvestigate the conditions on Atlantic Avenue, Brooklyn, and evolve somescheme for the elimination of grade crossings on that avenue. Early in1896 plans were prepared and presented to this Commission; first, for asubway from Flatbush Avenue Terminal for the entire distance to thelimits of the City of Brooklyn at Eldert's Lane; second, for a subwayfrom the Flatbush Avenue Terminal to East New York, Manhattan Crossing, the railroad to remain as it previously existed at grade through the26th Ward of Brooklyn. Each of these schemes contemplated an extensionthrough Brooklyn to New York City at Cortlandt Street and Broadway, andsurveys and borings for this work were made across the East River. Inthe summer of 1896, on the decease of Mr. Corbin, all projects and workwere immediately stopped; but, after some months, Mr. W. H. Baldwin, Jr. , when elected President of the Long Island Railroad Company, took upactively the reconsideration of the means whereby the Long IslandRailroad could reach New York City. After the fullest consideration, hedecided that the Blackwell's Island Bridge was by no means a suitable, adequate, or convenient entry for the Long Island Railroad into New YorkCity, as it involved too great a cost and altogether too rigid aconnection; it was also a very inconvenient location, inasmuch as it wascut off from convenient access to the west side of New York City byCentral Park. 

For the down-town connection, Mr. Baldwin became enthusiastic, but hehad in mind, throughout, the all-important necessity for the Long IslandRailroad to reach the Pennsylvania Railroad across the North River. Atthe same time Mr. Baldwin took up energetically the Atlantic AvenueImprovement with the Atlantic Avenue Commission, and, on consideration, decided it was essential that it should extend through the 26th Wardabove or below grade. The better plan, of course, was obviously to makeit a subway throughout, but, further, the residents of this wardobjected to the subway through that section, and that construction wouldhave made any change of the Manhattan Beach Division at ManhattanCrossing very difficult for the future; besides this, the controllingfactor was the absolute limitation by the City of Brooklyn of the amountof expenditure therefor in which they would participate, therefore acomposite scheme, which is the plan as carried out, was agreed upon, being in part subway and part elevated. This scheme reached a focusearly in 1897, and the law constituting the Board for the AtlanticAvenue Improvement was passed, with a provision in the last paragraph ofthe Act, for the construction of a tunnel from Flatbush Avenue Terminalunder Flatbush Avenue and Fulton Street to Pineapple Street, crossingthe river to Broadway and Maiden Lane (Cortlandt Street), New York City, and with the understanding that it would be extended beyond the New YorkState Line to the Pennsylvania Railroad Station in New Jersey. This gavethe legal right for the construction of this tunnel, and, on June 20th, 1899, the New York and Long Island Terminal Railroad Company wasincorporated for the purpose, Mr. Baldwin being President and J. V. Davies, M. Am. Soc. C. E. , Chief Engineer. Application was immediatelymade to the Boards of Aldermen of Brooklyn and of New York City. Thelatter acted favorably on the application, but the Board of Aldermen ofBrooklyn held the matter up, while the Rapid Transit Commission laid outand promulgated the plan for Contract No. 2 of the Rapid Transit Subway. With the understanding that the Rapid Transit Brooklyn extension wouldbe constructed to the Flatbush Avenue Terminal, Mr. Baldwin withdrew theapplication for the independent franchise, and agreed to proceed withthe Atlantic Avenue Improvement, on the basis of the City proceedingwith the Brooklyn extension of the Rapid Transit Subway. This providedfor the Long Island Railroad entry down town. 

[Illustration: PLATE V. --NEW YORK UNDERGROUND RAILWAY COMPANY SectionThrough Surface and Underground Stations]

Subsequently, however, it was proved that Mr. Baldwin had not been fullysatisfied that this was the proper solution of the matter, for on April12th, 1901, and upon his recommendation, the Board of Directors of theLong Island Railroad Company took over from the Pennsylvania RailroadCompany its entire interests in the old Brooklyn, New York, and JerseyCity Terminal Railway Company, thus giving him control of the route fromFlatbush Avenue _via_ Maiden Lane and Cortlandt Street to underneath theJersey City station. 

In the early part of 1900 active consideration was being given by thePennsylvania Railroad and other railroads terminating in New Jersey tothe proposed North River Bridge, as hereinbefore stated, and, for theLong Island Railroad, Mr. Baldwin organized a new company to construct atunnel from the Long Island Railroad at Sunnyside Yard, diving under thestreets of Long Island City by two tracks under the East River to thefoot of 33d Street and then proceeding under 33d Street as far asSeventh Avenue. A station was to be located at Fourth Avenue below theRapid Transit Subway Station and also a large Terminal Station atBroadway. For this purpose an option was obtained on the property of theNewbold Lawrence Estate, at Broadway, Sixth Avenue, 33d and 34thStreets, now occupied by Saks' Store. Mr. Baldwin, however, consideredthat the amount of the investment ($1, 600, 000) for that property was toogreat for this purpose, and allowed the option to expire. The propertywas sold within a week thereafter to the Morganthau Syndicate for$2, 000, 000. At this time (May, 1900), the Pennsylvania Railroad obtaineda controlling interest in the Long Island Railroad, and thereafter thetwo schemes became one. Mr. Baldwin and Mr. Rea purchased two 25-ft. Lots on 33d Street just east of Broadway for an entrance to theunderground station. Plans were also prepared for extending this linefrom Seventh Avenue northward under Seventh Avenue to 45th Street. Theinvestigation and preliminary work in connection with this project werecarried out in the early part of 1900. 

Reconsideration was given by Mr. Baldwin to the proposed location of theup-town tunnels, with the idea of connecting the New York Central andHudson River Railroad by a tunnel between Long Island City (Long IslandRailroad Station) and the foot of 42d Street and extending to the GrandCentral Station, but nothing further than investigation and thepreparation of estimates was done on this. 

In the summer of 1901 Mr. Cassatt was in Paris and was advised by Mr. Rea of the opening of the extension of the Orleans Railway to the Quaid'Orsay Station and its successful operation by electric power, also ofthe possibility of the Pennsylvania Railroad reaching New York City in asimilar way (the other trunk lines not having joined in the promotion ofthe North River Bridge project). He at once examined the new line, andthen consulted the writer in London in relation to the possibility ofbuilding tunnels under the North River. The writer returned to New Yorkwith Mr. Cassatt, and soon thereafter a conference of Mr. Cassatt, Mr. Rea, and Mr. Baldwin with the writer and Mr. Davies was held in thePennsylvania Railroad Company Office in New York, when Mr. Cassattoutlined the scheme practically as it is now carried out, the onlydifference being that he also proposed a station on property of the NewYork and Harlem Railroad Company at 33d Street, which was soon abandonedon account of the grade from the East River, and particularly becauseof the superior location of the adopted site at Seventh Avenue and 33dStreet, this being central between the down-town commercial andfinancial district and Central Park, which divides New York City. On Mr. Cassatt's instructions, surveys and investigations were begun inNovember, 1901, and estimates, drawings, etc. , were made. Preliminaryestimates were presented to him on November 8th, 1901. Following this, borings were continued, and a plan was presented to Mr. Cassatt forassisting the support of the North River tunnels on piles, if necessary. At the time of the appointment of the Board of Engineers and the generalorganization of the work, the preliminary investigations and work hadbeen carried to an advanced state. 

One result of the determination of the Pennsylvania Railroad Company toextend its lines into New York City and thus move its principal stationfrom Jersey City, was that the down-town local and suburban as well asthrough business was not provided for properly. Mr. William G. McAdoo, appreciating this opportunity, revived the scheme of an electric subwayfrom Jersey City to New York, originally promoted by Mr. Corbin andassociates, but not including the extension _via_ Maiden Lane toBrooklyn, and entered into negotiations with the Pennsylvania RailroadCompany to provide for this down-town business by extensions of thetunnel lines of the New York and New Jersey Railroads to Exchange Place, Jersey City, under the Pennsylvania Railroad Station, and thence acrossthe Hudson River to Cortlandt and Church Streets. As a result, theHudson and Manhattan Railroad Company was organized in 1902, andcontracts were made with the Pennsylvania Railroad Company for thesub-surface use of its station in Jersey City, and for the interchangeof passenger business at that point between the trains of thePennsylvania Railroad Company and the tunnel of the Hudson and ManhattanRailroad Company. Later, a further contract was made with thePennsylvania Railroad Company providing for the construction of thetunnel of the Hudson and Manhattan Railroad Company westward under thetracks of the Pennsylvania Railroad in Jersey City to a junction withthe latter at Summit Avenue, at which point can be installed a jointstation, and the operation effected of a joint electric train servicebetween Church Street, New York City, and Newark, N. J. , thePennsylvania Railroad tracks between Summit Avenue and Newark to beelectrified for that purpose, with a transfer station established eastof Newark, at Harrison, at which point the steam and electriclocomotives will exchange. By means of this, all down-town passengerswill transfer to the electric service at Harrison Station, and thus thePennsylvania Railroad Company is expected to be relieved of maintaininga separate steam service for passenger traffic to Jersey City and alarge down-town station with extensive contingent facilities at thatpoint. 

From the foregoing it will be seen that the final decision to extend thePennsylvania Railroad into and through New York City by a system oftunnels, and erect a large station in that city on a most eligible site, was not reached in a hurried or off-hand manner, but after years ofpainstaking study and a full and extended investigation of all routes, projects, and schemes, whether originating with the company or suggestedby others. 

[Illustration: Plate VI. --Pennsylvania Railroad Extension:Map Showing Proposed Lines Leading to Those Finally Adopted]

Plate VI is a map of New York City and vicinity on which are shown thevarious lines contemplated in the evolution of the New York TunnelExtension of the Pennsylvania Railroad hereinbefore outlined. 

The question of tunnels under the North River was an uncertain factor inthe larger Pennsylvania Railroad scheme, owing to the nature of theground composing the river bed in which the tunnels would beconstructed. 

It is well known that about 35 years ago an attempt was made toconstruct a tunnel under the North River by using a "Pilot" system undercompressed air and forming the tunnels in brick masonry. Owing to thevery soft nature of the materials through which it passed, severalserious accidents occurred, and the work was abandoned after about 2, 000ft. Of tunnel had been constructed. Later, this work was taken up again, when a shield was installed and an additional 1, 800 ft. Was built withcast-iron segmental lining, but the work was again abandoned, owingprincipally to financial difficulties while coincidentally beforeentering a rock reef which presented another serious difficulty inconstruction. The experience then in the construction of this tunnel ledcapitalists and engineers to believe that, owing to the very soft natureof the ground, a tunnel could not be built that would be sufficientlystable to withstand the vibration due to heavy traffic, and for thisreason tunnels under the North River were not looked upon aspracticable. The writer devised a scheme to carry within the tunnel therolling loads on bridging supported on piers or piles extending fromthe tunnel invert down to hard material. These would be attached to thetunnel itself or would pass into it independently through sliding jointsin the tunnel shell. This scheme gained the confidence of themanagement, as it was believed that, by adopting such a plan, tunnelscould be built in the soft material underlying the Hudson River andremain stable under all conditions of traffic. After thus feelingassured that by this method the tunnels could be made safe beyondquestion, orders were given to proceed with the great work of theextension into New York of the Pennsylvania and Long Island Railroadsystems. 

[Illustration: FIG. 1. --(Full page image)

ENGINEERING STAFF ORGANIZATION

CHIEF ENGINEER |CHIEF ASSISTANT ENGINEER | | +--(CHIEF OFFICE) | | | +--OFFICE ENGINEER | | | | | +--Chief Draftsman. | | Draftsmen. | | Messenger. | | | +--MECHANICAL ENGINEER | | | | | +--Mechanical Draftsmen. | | | +--ASSISTANT ENGINEER | | | +--Accountant. | Clerks. | Telephone Operators. | Messenger. | | +--(TERMINAL STATION WEST) | | | RESIDENT ENGINEER | | | +--Assistant Engineer. | | Chief of Party. | | Instrumentmen. | | Rodmen. | | Chainmen. | | | +--Inspectors. | | | +--Clerk. | Janitors. | | +--(SUBAQUEOUS, 32ND STREET AND WEEHAWKEN TUNNELS) | | | GENERAL RESIDENT ENGINEER | | | +--Cement Inspectors. | | Ass't. Cement Inspectors. | | | +--Photographer. | | | +--Recording Clerk. | | Ass't. Recording Clerks. | | | +--DISPATCH BOAT | | | | | +--Captains. | | Engineers. | | Deckhands. | | Messenger. | | | +--RESIDENT ENGINEERS | | | +--(CONSTRUCTION) | | | | | +--Ass't. Engineers. | | Chief Tunnel Inspectors. | | Tunnel Inspectors. | | Surface Inspectors. | | Clerks. | | | +--(ALIGNMENT) | | | | | +--Ass't. Engineers. | | Chiefs of Parties. | | Instrumentmen. | | Rodmen. | | Chainmen. | | Rear Chainmen. | | Laborers. | | | +--(OFFICE STAFF) | | | +--Draftsmen. | Field Office Clerks. | Cement Warehousemen. | Janitors. | Messengers. | +--(MEDICAL DEPARTMENT) | | | CHIEF MEDICAL OFFICER | Ass't. Medical Officer. | | +--(BERGEN HILL TUNNELS) | | | RESIDENT ENGINEER | Assistant Resident Engineer | | | +--Assistant Engineer. | | Instrumentmen. | | Rodmen. | | Chainmen. | | | +--Inspectors. | | Cement Warehousemen. | | | +--Clerk. | Janitors. | | +--(METAL INSPECTION) | CHIEF METAL INSPECTOR Metal Inspectors. Clerks. ]

The organization of the engineering staff is shown on the diagram, Fig. 1. In the beginning of 1902 and during the period of making studies, additional borings, and preliminary triangulations, and prior to makingthe contract plans and specifications, James Forgie, M. Am. Soc. C. E. , was appointed Chief Assistant Engineer by the writer. To him all theResident Engineers and other heads of the Engineering Departmentsreported. 

The work was divided into three Residencies:

1. --The Terminal Station-West, under the charge of B. F. Cresson, Jr. , M. Am. Soc. C. E. , Resident Engineer, comprising the work from the eastside of Ninth Avenue to the east side of Tenth Avenue, includingexcavation, retaining and face walls, and the extensive work ofunderpinning Ninth Avenue with its surface and elevated railroads andother structures. 

2. --The River Tunnels, under the charge of B. H. M. Hewett, M. Am. Soc. C. E. , General Resident Engineer, and Mr. H. F. D. Burke and WilliamLowe Brown, M. Am. Soc. C. E. , Resident Engineers, including the landtunnels from the east side of Tenth Avenue, New York City, to thecommencement of the iron-lined tunnels, and extending westward fromthere to the Weehawken Shaft, New Jersey. 

3. --The Bergen Hill Tunnels, under the charge of F. Lavis, M. Am. Soc. C. E. , Resident Engineer, including the rock tunnels from the WeehawkenShaft to the Hackensack Portal on the west side of the Palisades, all inNew Jersey. 

Paul A. Seurot, M. Am. Soc. C. E. , acted as Office Engineer in charge ofthe drawing office, and Mr. J. Soderberg as Mechanical Engineer incharge of the mechanical drafting. Prior to the construction of theabove works Mr. C. J. Crowley acted as Resident Engineer on theconstruction of the Weehawken Shaft, and J. F. Rodenbough, Assoc. M. Am. Soc. C. E. , on that of the Manhattan Shaft. 

Table 1 shows the quantities of certain materials and other statisticsregarding this Division. 

TABLE 1. 

------------------------------------------+---------+-----------+---------- | Bergen | River | Term. | Hill. | Tunnels. | Sta. -W. +---------+-----------+---------- | | |Excavation disposed of (or displaced), | | | in cubic yards | 263, 000 | 238, 995 | 517, 000Cast metal used in tunnel, including | | | cast iron and cast steel, in tons | | 64, 265 |Steel bolts used, in tons | | 2, 606 |Cement used (concrete and grout), | | | in barrels | 95, 000 | 145, 500 | 33, 000Concrete, in cubic yards | 95, 000 | 75, 400 | 18, 500Dynamite for blasting, in pounds | 600, 000 | 100, 400 | 206, 000Brickwork, in cubic yards | | 4, 980 |Structural steel (including Pier 72), | | | in pounds | 50, 000 | 3, 141, 000 | 1, 475, 000------------------------------------------+---------+-----------+----------

The number of passengers carried on the Elevated Railroad and surfacelines of Ninth Avenue during the underpinning of these structures wasabout 125, 000, 000. 

The Board of Engineers, organized by the Pennsylvania Railroad Companyin January, 1902, immediately took up the matter of route and grade. Thecenter line, which had been assumed as the center line of 32d Streetextended westward, was slightly changed. 

The grade adopted was approximately 2% descending westward from NinthAvenue, which would place the tunnel well below the Government dredgingplane of 40 ft. Below mean low water at the pier head line; thencewestward on a lighter grade still descending until the deepest portionof the river was reached where the top of the rail would be about 90 ft. Below mean high water, this location giving sufficient cover over thetunnels to insure stability and guard against the possibility ofshipwrecks settling on the tunnels. From this point to the portal anascending grade of 1. 30% was adopted, which gave the lines sufficientelevation to cross over the tracks of the New York, Susquehanna andWestern and the Erie Railroads, which run along the westerly base of thePalisades. Owing to the exigencies of construction, these grades in theriver were very slightly modified. Plate VII is a plan and profile ofthe tunnels as constructed. 

[Illustration: Plate VII. --Plan, Profile, and Triangulation, North RiverTunnels]

The Board of Engineers early in 1902 took up the question of supportsfor the tunnels under the North River, and various plans and schemeswere considered. It was finally decided to support the tracks onscrew-piles carried through the lining of the tunnels, as originallyproposed by the writer. 

In order to know something of the capacity of screw-piles in the actualmaterial to be passed through, it was resolved to test them. A caissonwas sunk at the end of one of the Erie Railroad piers on the New Jerseyside near the line of the tunnels, and, to obtain parallel conditions asmuch as possible, the excavation was carried down to the proposed gradeof the tunnel. Various types of screw-piles were sunk therein and testswere made, not only of the dead load carrying capacity, but also withthe addition of impact, when it was found that screw-piles could be sunkto hard ground and carry the required load. The final part of the testwas the loading. The screw-pile, having a shaft 30 in. In diameter and ablade 5 ft. In diameter, was loaded with 600, 000 lb. , with the resultthat, for a month--the duration of this loaded test--there was nosubsidence. 

Again, and after the iron tunnel lining had been constructed across theriver, tests were made of two types of supports: One a screw-pile 29-1/2in. In diameter with a blade 4 ft. 8 in. In diameter and the other awrought-iron pipe 16 in. In external diameter. Tests were made, not onlyfor their carrying capacity, but also for their value as anchorages, andit was found that the screw-pile was more satisfactory in every way; itcould be put down much more rapidly, it was more easily maintained in avertical position, and it could carry satisfactorily any load whichcould be placed on it as a support for the track. The 16-in. Pipe didnot prove efficient either as a carrier or as an anchorage. These testswill be mentioned in the detailed description of the work to follow. Figs. 2 and 3 illustrate the general arrangement and details of themachine designed by the writer and used for sinking the test piles inthe tunnels. This machine had been used originally on the New Jerseyside on the test pile at Pier C, and the adaption was not exactly asshown on these drawings, but if the screw-piles had been placed in thetunnels, the arrangement shown would have been used. 

Surveys, soundings, and borings were commenced in the latter part of1901 on an assumed center line of tunnels which was the center line of32d Street extended westward. 

The soundings were made from a float stage fastened to a tugboat, thelocation being determined by transits on shore and the elevation bymeasuring from the surface of the water, a tide gauge being continuallyobserved and the time of soundings and gauge readings kept. 

In the river wash-borings were made from a floating pile-driver on whichwas installed a diamond-drill outfit of rods, pump, etc. Fourteenborings were completed in the river. Considerable difficulty was foundin holding the pile-driver against the current, the material in thebottom being very soft, and several borings were lost owing to thedrifting of the pile-driver. Each boring was continued, and the depth ofseveral was more than 250 ft. Below the surface of the water. Theborings on land were mostly core borings, and were generally made withthe chilled shot boring machine. 

Base lines, about 2, 250 ft. In length, were measured on each side of theriver, and observation points established. It was necessary to build atriangulation tower 60 ft. High on the New Jersey side as an observationpoint. The base lines were measured with 100-ft. Steel tapes which weretested repeatedly, and the work was done at night in order to obtain thebenefit of uniform temperature and freedom from traffic interruptions. From the base line on the New Jersey side, which passed over theWeehawken Shaft, an elevated point on the assumed center line on theside of Bergen Hill was triangulated to, and from this point westward aclosed polygon was measured along the streets to the top of the hill onthe west side and thence along the assumed center line to the portal. The level transfer across the river was made by sighting across inopposite directions simultaneously, and also by tide gauges. The outlineof the final triangulation system is shown on Plate VII. 

[Illustration: FIG. 2. --(Full page image)

HYDRAULIC SCREWING MACHINE WITH RATCHET DRIVE AND VERTICAL JACK

GENERAL ARRANGEMENT]

[Illustration: FIG. 3. --(Full page image)

HYDRAULIC SCREWING MACHINE WITH RATCHET DRIVE AND VERTICAL JACK

DETAILS]

The decision as to the locations of the shafts on both sides of theriver, for construction purposes and finally for permanent use, was acomparatively simple matter, and, all circumstances considered, they areunquestionably in the most suitable places. On the New York side theshaft was as near as practicable to the line dividing the subaqueousiron-lined tunnels from the land tunnels, and on the New Jersey side theshaft was placed centrally on the line of the tunnels and on the nearestavailable ground to the river, while at the same time beyond the otherend of the river tunnels, thus necessitating driving the subaqueoustunnels only from east and west to meet under the river. A caisson shafton the New York side, on the line of the tunnels near the riverbulkhead, was at one time considered, but was not adopted as itentailed the driving of two shields both east and west, in addition tothe two from New Jersey, adding to the plant outlay while not affordingany material saving in the time of construction. 

It was thought desirable to construct the shafts on the two sides of theriver in advance of letting the main contracts for the tunnels. TheManhattan Shaft is north of the line of the tunnels, on the north sideof 32d Street, east of Eleventh Avenue. The Weehawken Shaft is on theline of the tunnels in the yards of the Erie Railroad on the New Jerseyside, and the distance between the shafts is about 6, 575 ft. Thecontracts for these shafts were let in June, 1903, to the UnitedEngineering and Contracting Company, and they were completed and readyfor use at the time of letting the main contract for the tunnels, thussaving considerable time. 

_The Terminal Station-West. --Between Ninth and Tenth Avenues. _--In theoriginal design it was contemplated to have a four-track tunnel under32d Street from Ninth to Eleventh Avenues, but owing to the necessityfor having additional yard facilities, property was bought for about 100ft. North and 100 ft. South of 32d Street, between Ninth and TenthAvenues, and an open excavation, lined with concrete retaining walls andface walls, was made. Between Ninth and Tenth Avenues, 32d Street wasclosed, and the property formerly the street was bought by the TunnelCompany from the City of New York for a consideration by deed datedApril 18th, 1906. The Church, Rectory, and School of St. Michael's, which was located on the west side of Ninth Avenue between 31st and 32dStreets, was acquired by the Tunnel Company after it had acquiredproperty for and had built a similar institution on the south side of34th Street west of Ninth Avenue. 

Probably the most interesting feature of this contract was the supportand maintenance of Ninth Avenue, which has a three-track elevatedrailway structure and a two-track surface railway structure, on which itwas necessary to maintain traffic while excavation was made to a depthof about 60 ft. , and a viaduct was erected to carry Ninth Avenue. Thelength of this viaduct is about 375 ft. , and the steelwork and itserection was done apart from the North River Division work, but allexcavation and underpinning was included in this division. The contractfor this work on the Terminal Station-West was let to the New YorkContracting Company-Pennsylvania Terminal, on April 28th, 1906, andincluded about 517, 000 cu. Yd. Of excavation, about 87% being rock, theconstruction of about 2, 000 lin. Ft. Of retaining and face wallscontaining about 18, 500 cu. Yd. Of concrete, and a large quantity ofstructural steel (1, 475, 000 lb. ) for temporary use in underpinning NinthAvenue. 

Fig. 4 shows cross-sections of the Terminal Station-West yard, and Fig. 5 shows the general method of underpinning the Ninth Avenue structures. 

[Illustration: FIG. 4. --TERMINAL STATION WEST

TYPICAL SECTIONS]

_River Tunnels. _--In the original plan a four-track tunnel wascontemplated from the east side of Tenth Avenue to the east side ofEleventh Avenue, but, owing to the extension of the Terminal Yard, previously noted, this plan was changed, and a two-track structure wasbuilt having a central wall between the tracks. This was constructed intunnel, with the exception of 172 ft. About midway between Tenth andEleventh Avenues, where the rock dipped below the roof of the tunnel, and there the construction was made in open cut. These tunnels werelined with concrete with brick arches, Figs. 6, 7, and 8 being typicalcross-sections. This work was executed by the O'Rourke EngineeringConstruction Company, under a contract dated November 1st, 1904. 

It was possible to excavate in full rock cover about 250 ft. Of thetunnels eastward from the Weehawken Shaft and 225 ft. Westward from theManhattan Shaft. At these points the rock cover was very thin, and thereshield chambers were made for the erection of two sets of shields, about6, 100 ft. Apart. A typical cross-section of the Weehawken Land Tunnel isshown on Plate VIII. 

[Illustration: Plate VIII. --Typical Sections Between Manholes, BergenHill Tunnels]

The Board of Engineers decided, and it was so stated in the contract andspecifications, that the river tunnels should be constructed by means ofhydraulic shields, but bidders were permitted to present to the Boardany scheme on which they might desire to bid, but, of course, thedecision as to the practicability of such plans rested with the Board. 

Inasmuch as the shield method of construction was required, the writerdesigned a shield for use in the North River Tunnels. The shield wasabout 18 ft. Long, over all, and was provided with a rigid but removablehood extending beyond the normal line of the cutting edge, for use insand, gravel, and ballast, to be removed when the shield reached thesilt. The shields were thrust forward by twenty-four rams capable ofexerting a pressure of 3, 400 tons at a hydraulic pressure of 5, 000 lb. Per sq. In. Taking into account 30 lb. Air pressure, this pressure wasincreased to 4, 400 tons. The shield was fitted with a single hydraulicerector and hydraulic sliding platforms, and when complete weighed 194tons. Fig. 9 is a back elevation and section of the shield. 

The contract for the river tunnels was let to the O'Rourke EngineeringConstruction Company on May 2d, 1904. 

The shields were built in accordance with the design previously referredto, and proved entirely satisfactory. Generally, the materials passedthrough were as follows: Starting out in full face rock, from it into amixed face of rock and sand, thence into sand and gravel, full face ofsand, piles, rip-rap, and the Hudson silt; and all were fully chargedwith water. 

Compressed air, at an average gauge pressure of about 25 lb. And amaximum of 40 lb. Per sq. In. , was used in the tunnels from the time theshields emerged from full rock face until the tunnel lining had beenjoined up and all caulking and grummeting had been done. 

[Illustration: FIG. 5. --(Full page image)

ARRANGEMENT OF STRUCTURES SUPPORTING NINTH AVE. DURING PROGRESS OFEXCAVATION]

Contractor's plants were established at the Weehawken Shaft and at theManhattan Shaft, including at each, low-pressure air compressors of acapacity of 13, 000 cu. Ft. Of free air per minute and also high-pressureair compressors for drills, hydraulic pumps, electric generators, etc. 

The river tunnels passed under Pier 72, North River (old No. 62), whichwas occupied by the New York Central and Hudson River Railroad Company. The Tunnel Company leased this pier and withdrew all the piles on thelines of the tunnels prior to the commencement of construction, and onthe remaining piles constructed a trestle for the disposal of theexcavation from the tunnels and the terminal. At the completion of thework this pier had to be restored, and Fig. 10 shows the generalarrangements of the location of the piles and the pier structure withreference to the tunnels. 

In the tunnels which were constructed in silt farther down the river, bythe writer as Chief Engineer for the Hudson Companies, it had beenpossible to shove the shield through the silt with all the doors closed, displacing the ground and making great speed in construction owing tothe absence of all mucking. It was thought that this procedure might bepursued in the larger tunnels of the Pennsylvania Railroad, and it wastried, but it was almost immediately found to be impossible to maintainthe required grade without taking a certain quantity of muck into thetunnels through the lower doors, the tendency of the shield being torise. By taking in about 33% of the excavation displaced by the tunnel, the grade could be maintained. It was considered desirable, owing tothis rising of the shields, to increase the weight of the cast-ironlining, and this was done, making the weight of the completed tunnelmore nearly equal to the weight of the displaced material. The weight ofthe cast-iron lining (with bolts) was increased from 9, 609 to 12, 127 lb. Per lin. Ft. Of tunnel. The weight of the finished tunnel with thisheavier iron is 31, 469 lb. Per lin. Ft. The weight of the silt displacedper linear foot of tunnel, at 100 lb. Per cu. Ft. , is 41, 548 lb. Theweight of the completed tunnel with the maximum train load is 42, 869 lb. Per lin. Ft. 

The maximum progress at one face in any one month was 545 ft. , workingthree 8-hour shifts, and the average progress in each heading whileworking three shifts was 18 ft. Per 24 hours; while working one shiftwith the heavier lining referred to above, the delivery of which wasslow, the average progress was 11 ft. Per 24 hours. 

[Illustration: FIG. 6. --15' 4" Span Twin Tunnels. Rock Roof. ]

[Illustration: FIG. 7. --19' 6" Span Twin Tunnels. ]

[Illustration: FIG. 8. --21' 6" Span Twin Tunnels]

[Illustration: FIG. 9. --PROPOSED SHIELD FOR SUBAQUEOUS TUNNELING GENERALELEVATION]

[Illustration: FIG. 10. --RESTORATION OF PIER 72 (OLD 62) NORTH RIVERTRANSVERSE SECTION AT CENTER OF PIER]

In order to permit the screw-piles to be put in place through thelining, cast-steel bore segments were designed, and placed in the invertat 15-ft. Centers; these are of such a design as to permit the blade andshaft of the screw-pile to be inserted without removing any portion ofthe lining. Fig. 11 is a typical cross-section of the river tunnel, asoriginally planned, with these pile supports. 

After the shields had met and the iron lining was joined up, variousexperiments and tests were made in the tunnel; screw-piles, and 16-in. Pipes, previously referred to, were inserted through the bore segmentsin the bottom of the tunnel, thorough tests with these were made, levelswere observed in the tunnels during the construction and placing of theconcrete lining, an examination was conducted of the tunnels of theHudson and Manhattan Railroad Company under traffic, and the result ofthese examinations was the decision not to install the screw-piles. Thetunnels, however, were reinforced longitudinally by twisted steel rodsin the invert and roof, and by transverse rods where there was asuperincumbent load on the tunnels; it might also be noted that on theNew York side, where the tunnels emerge from the rock and pass into thesoft material, the metal shell is of cast steel instead of cast iron. Fig. 12 is a typical cross-section of the river tunnels as actuallyconstructed. 

[Illustration: FIG. 11. --(Full page image)

CROSS-SECTION OF TUNNEL SHOWING TRACK SYSTEM AND SCREW-PILE. ]

[Illustration: FIG. 12. --SUBAQUEOUS TUNNELS CROSS-SECTIONS]

During the investigations in the tunnels, borings were made to determineexactly the character of the underlying material, and it was then foundthat the hard material noted in the preliminary wash-borings was a layerof gravel and boulders overlying the rock. When the borings in thetunnels reached this material it was found to be water-bearing and thehead was about equivalent to that of the river. Rock cores were takenfrom these borings, and the deepest rock was found at about the centerof the river at an elevation of 302. 6 ft. Below mean high water. Rodswere then inserted in each bore hole and thereby attached to the rockand used as bench-marks in the tunnels. From these bench-marks, usingspecially designed instruments, very accurate observations of thebehavior of the tunnels could be made, and from these the veryinteresting phenomenon of the rise and fall of the tunnels with the tidewas verified, the tunnels being low at high tide and the averagevariations being about 0. 008 ft. In the average tide of about 4. 38 ft. :the tidal oscillations are entirely independent of the weight of thetunnels, since observations show them to have been the same both beforeand after the concrete lining was in position. There was considerablesubsidence in the tunnels during construction and lining, amounting toan average of 0. 34 ft. Between the bulkhead lines. This settlement hasbeen constantly decreasing since construction, and appears to have beendue almost entirely to the disturbances of the surrounding materialsduring construction. The silt weighs about 100 lb. Per cu. Ft. (this isthe average of a number of samples taken through the shield door, andvaried from 93 to 109 lb. Per cu. Ft. ), and contains about 38% of water. It was found that whenever this material was disturbed outside thetunnels a displacement of the tunnels followed. The tunnels as abovenoted have been lined with concrete reinforced with steel rods, andprior to the placing of the concrete the joints were caulked, the boltsgrummeted, and the tunnels rendered practically water-tight; the presentquantity of water to be disposed of does not exceed 300 gal. Per 24hours in each tunnel 6, 100 ft. Long. 

_Bergen Hill Tunnels. _--These are two single-track tunnels, 37 ft. Fromcenter to center, and extend for a distance of 5, 940 ft. From theWeehawken Shaft to the Hackensack Portal. They were built almostentirely through trap rock. The contract was let on March 6th, 1905, tothe John Shields Construction Company, but was re-let on January 1st, 1906, to William Bradley, the Shields Company having gone into the handsof a receiver. About 1, 369 ft. Of the tunnel excavation was done by theShields Company, but no concrete lining. The maximum monthly progressfor all headings was 622 ft. , and the average progress was 338 ft. Aworking shaft 216 ft. Deep was sunk from the top of the hill, tofacilitate construction. The tunnels are lined with concrete throughout. Typical cross-sections of these tunnels are shown on Plate VIII. 

In conclusion it may be admissible for the writer after having, inconjunction with Mr. Samuel Rea, experienced the evolution andmaterialization of this Pennsylvania Railroad scheme, to express hisgreat sorrow for the untimely death of the father of the entire scheme, the late President Cassatt.