Grand Central Terminal is a commuter rail terminal located at 42nd Street and Park Avenue in Midtown Manhattan, New York City. Grand Central is the southern terminus of the Metro-North Railroad's Harlem, Hudson and New Haven Lines, serving the northern parts of the New York metropolitan area. It also contains a connection to the Long Island Rail Road through the Grand Central Madison station, a 16-acre (65,000 m2) rail terminal underneath the Metro-North station, built from 2007 to 2023. The terminal also connects to the New York City Subway at Grand Central–42nd Street station. The terminal is the third-busiest train station in North America, after New York Penn Station and Toronto Union Station.

The New Haven Line is a 72.7 mi (117.0 km) commuter rail line operated by the Metro-North Railroad in the U.S. states of New York and Connecticut. Running from New Haven, Connecticut, to New York City, the New Haven Line joins the Harlem Line in Mount Vernon, New York, and continues south to Grand Central Terminal in Manhattan. The New Haven Line carries 125,000 passengers every weekday and 39 million passengers a year. The busiest intermediate station is Stamford, with 8.4 million passengers, or 21% of the line's ridership.