Metro-North Railroad is currently planning to reinstitute local commuter service on the line as part of the first phase of Penn Station Access.

[6] In June 1906, the NH applied for and received a franchise to operate trains from the northeastern suburbs of New York City to Pennsylvania Station in Midtown Manhattan, built by the PRR.

[8] Construction was overseen by Gustav Lindenthal, whose original design left a gap of 15 feet (4.6 m) between the steel arch and the masonry towers.

The design was changed to smooth concrete to soothe concerns that asylum inmates on Wards and Randall's islands would climb the piers to escape.

[9] The engineering was so precise that when the last section of the main span was lifted into place, the final adjustment needed to join everything together was just 5⁄16 inch (7.9 mm).

The original electrification extended from the New Haven's main line, across the Hell Gate Bridge, to the Bay Ridge yard.

[14][15] The bridge opened on March 9, 1917,[11] but was operated by steam with an engine change at Sunnyside Yard east of Penn Station until 1918.

The New York, Westchester and Boston Railway commuter rail line opened in 1912, paralleling the HR&PC just to the west, south of the crossing of the Bronx River.

This allowed NYNH&H trains to run over the HR&PC and into New York Penn Station, though most continued to serve Grand Central Terminal until Amtrak took over intercity operations in 1971.

Penn Central was required to absorb the New Haven in 1969 as a condition of the merger, which brought the entire Washington–Boston corridor under the control of one company.

A 1969 proposal by the North Bronx Transportation Project considered running trains via the Hell Gate Bridge to Penn Station, with travel times estimated to be 25 minutes.

Some plans for the Second Avenue Subway included integration with the upper portion of the line, providing express service from the East Side of Manhattan to Co-op City and Parkchester.

[19] The Penn Station Access project was initiated on September 2, 1999 when the Federal Transit Administration (FTA), in conjunction with Metro-North Railroad, issued a Notice of Intent (NOI) to prepare a Major Investment Study/Environmental Impact Statement (EIS).

The EIS was intended to consider possible additions to Metro-North using existing rail lines, with the intention of providing flexibility and increased regional access.

Using a newly-constructed wye track at Spuyten Duyvil, service would turn south via the Empire Connection before reaching Penn Station.

Another option considered would have constructed a wye track at Woodlawn, allowing Harlem trains to go east and head down the Hell Gate Line to Penn Station.

This phase includes the construction of four new Metro-North stations in the Bronx to be served by the New Haven Line, located in Co-op City, Morris Park, Parkchester/Van Nest, and Hunts Point.

[28] The stations would provide fast, direct rides to West Midtown and facilitate reverse-commuting trips to Westchester County and Connecticut.

[34] Since 2014, local residents have pushed to have a Metro-North station built in Queens, either between 41st and 44th Streets in Astoria, or at Northern Boulevard and Broadway in Woodside.

[37] In order to accommodate more trains, power and signal systems, and yards at Penn Station and New Rochelle[38] will be upgraded and three railroad bridges will be rehabilitated or replaced.

Regional connectivity will be increased with accessible transfers to Amtrak, the Long Island Rail Road and New Jersey Transit at Penn Station.

[50] The Federal Transit Administration (FTA) published a draft environmental impact statement in May 2021, and the state government commenced a request for proposals for the project's development.

[52] The expanded services will operate at Moynihan Train Hall, an expansion of Penn Station into the neighboring James A. Farley Building.