The Broadway Line is a rapid transit line of the division of the New York City Subway system. The line was built as a part of the Broadway-Fourth Avenue Subway and is also known as the Broadway-BMT Line and the Broadway (BMT) Subway. Trains of the and serve the express run via the Manhattan Bridge and the and lines the local via the Montague Street Tunnel . The line is often referred to as the N 'n' R due to the N and R services that were the only services which continued to operate over the line during the long years of closure of the Manhattan Bridge south tracks. Trains using this mainline are assigned the color yellow.

Extent and service

The Broadway-BMT Line begins at the 60th Street Tunnel from Queens and runs by the following alignment:

• West under 60th and 59th Streets as a two-track subway line, curving south into 57th Street (Broadway-BMT Line) station, where it joins two tracks of the BMT 63rd Street Line. This part of the line carries the N and W services from the Astoria Line and the R service from the Queens Boulevard Line.
• The 63rd Street Line forms the express tracks in 57th Street station, and the tracks from the 60th Street branch the local tracks. There is no scheduled BMT service on the 63rd Street Line at present. These tracks are planned to carry the Q service across 63rd Street and up the Second Avenue Line, when and if built. Therefore the express tracks at 57th Street are currently used as terminal tracks for the Q train.
• The Broadway-BMT Line proceeds as a four-track subway down 7th Avenue to its intersection with Broadway, and then continues down Broadway to a point north of Canal Street, where the express tracks carrying the Q and N services are lowered and turn sharply east into the Canal Street (formerly Broadway) station of the Manhattan Bridge Line.
• Immediately after Canal Street, the express tracks resume again (originally they had been intended to run through) and serve as storage and turning tracks, bypassing Canal Street local station and ending in the disused lower level of City Hall . The local tracks continue south as a two-track subway to Whitehall Street station. Whitehall Street is a three track, two-platform station, with the center track set up as a terminal track, currently used as the south terminal of W trains.
• The Broadway-BMT Line then curves east carrying the R service to a trailing junction with the Nassau Street Line and enters the Montague Street Tunnel to Brooklyn.