New York Tunnel Extension

The New York Tunnel Extension (also New York Improvement and Tunnel Extension) is a combination of railroad tunnels and approaches from New Jersey and Long Island to Pennsylvania Station in Midtown Manhattan. It was built by the Pennsylvania Railroad (PRR) at the beginning of the 20th century to improve railroad access throughout the greater New York metropolitan area, and led to the line's then-new passenger facility, Pennsylvania Station.

Source: Wikipedia — New York Tunnel Extension (CC BY-SA 4.0)