Some time before the appointment of the Board of Engineers whichsupervised the designing and construction of the New York TunnelExtension of the Pennsylvania Railroad, the late A. J. Cassatt, thenPresident of the Company, said to the writer that for many yearshe had been unable to reconcile himself to the idea that a railroadsystem like the Pennsylvania should be prevented from entering themost important and populous city in the country by a river less thanone mile wide. The result of this thought was the tunnel extensionproject now nearly completed; but it is only in recent years that newconditions have rendered such a solution of the problem practicable aswell as desirable.
Previously a tunnel designed for steam railroad traffic, to enterNew York City near Christopher Street, was partly constructed, butthe work was abandoned for financial reasons. Then plans for a greatsuspension bridge, to enable all the railroads reaching the west shore[2]of the North River to enter the city at the foot of 23d Street, werecarefully worked out by the North River Bridge Company. The PennsylvaniaRailroad Company gave this project its support by agreeingto pay its pro rata share for the use of the bridge; but the otherrailroads declined to participate, and the execution of this plan wasnot undertaken.
New operating conditions, resulting from the application of electrictraction to the movement of heavy railroad trains, which had beenused initially in tunnels by the Baltimore and Ohio Railroad and wassubsequently studied and adopted by railroads in Europe, made itpossible to avoid the difficulty of ventilation connected with steamtraction in tunnels, and permitted the use of grades practically prohibitivewith the steam locomotive. The practicability of the tunnelextension project finally adopted was thus assured.
The acquisition of the control of the Long Island Railroad by thePennsylvania Railroad Company, which occurred in 1900, introducednew and important elements into the transportation problem, from afreight as well as a passenger standpoint. Previously, the plans consideredhad for their only object the establishment of a convenientterminus in New York, to avoid the delays and difficulties involvedin the necessity of transporting passengers and freight across theNorth River. When the Long Island Railroad became practically apart of the Pennsylvania System, it was possible and desirable to extendthe project so as to provide, not only for a great prospective local trafficfrom all parts of Long Island, but also for through passenger andfreight traffic to the New England States, and to and from all pointson the Pennsylvania System, thus avoiding the long ferriage fromJersey City around the harbor to the Harlem River.
This paper has for its subject the New York Tunnel Extensionproject, and is intended merely as an introduction to the detailedaccounts of the construction of the various divisions of the line tobe given in succeeding papers prepared by the engineers who activelycarried out the work. The project, however, forms the most importantpart of the comprehensive scheme adopted by the Pennsylvania RailroadCompany for conducting its traffic into and through New YorkCity, and a brief description of this general plan is therefore necessaryin order that the relations o