Pennsylvania Tunnel and Terminal Railroad

New York Tunnel Extension
North Bergen portal of the tunnels
Overview
Type	Heavy rail, Commuter rail
System	Originally Pennsylvania Railroad now Amtrak, New Jersey Transit, Long Island Rail Road.
Status	In operation
Locale	New York City Hudson County, New Jersey
Operation
Opened	1910
Owner	Amtrak
Technical
Line length	44 miles (71 km) (total main line trackage)
Track gauge	1,435 mm (4 ft 8 1⁄2 in)
Electrification	650 V DC third rail (1910-1933). 11,000 V AC overhead lines (1933-present)
Route map

The New York Tunnel Extension (also New York Improvement and Tunnel Extension), was a major project of the Pennsylvania Railroad (PRR) at the beginning of the 20th century, to improve railroad access throughout the greater New York City area. The project comprised tunnels and approaches from New Jersey and Long Island to Midtown Manhattan, leading to the PRR's massive new station, New York Penn Station.

The PRR had consolidated its control of railroads in New Jersey with the lease of United New Jersey Railroad and Canal Company in 1871, thereby extending its rail network from Philadelphia northward to Jersey City. Crossing the Hudson River, however, remained a major obstacle. To the east, the Long Island Rail Road (LIRR) ended at the East River. In both situations, passengers had to transfer to ferries to Manhattan. This put the PRR at a disadvantage relative to its arch competitor, the New York Central Railroad, which already served Manhattan.

Various plans to cross the Hudson were discussed as early as the 1870s, and both tunnel and bridge projects were considered by the railroads and government officials. A tunnel project for the Hudson and Manhattan Railroad (H&M), a rapid transit line, began in 1874, and encountered serious engineering, financial and legal obstacles. The project was halted in 1880 after a blowout accident that cost 20 lives. (Work on the H&M project, known as the Uptown Hudson Tubes, continued intermittently but was not completed until 1908.)