The 3 Broadway – Seventh Avenue Express is a rapid transit service in the New York City Subway's A Division. Its route emblem, or "bullet", is colored red since it uses the IRT Broadway – Seventh Avenue Line through most of Manhattan.
The 3 operates between 148th Street in Harlem, Manhattan and New Lots Avenue in East New York, Brooklyn, making express stops in Manhattan and all stops in Brooklyn, except nights when it short turns at Times Square–42nd Street in Midtown, Manhattan.
On November 23, 1904, the IRT Lenox Avenue Line opened between 96th Street and 145th Street. 3 trains ran between 145th Street and City Hall, making all stops.
On July 1, 1918, the entire IRT Broadway–Seventh Avenue Line was completed. 3 trains were rerouted south of 42nd Street from the IRT Lexington Avenue Line to this new line. They now made all stops to South Ferry.
On August 23, 1920, the 3 was extended to/from New Lots Avenue in East New York, Brooklyn via the Clark Street Tubes, the IRT Eastern Parkway Line, and the IRT New Lots Line. Trains began making express stops in Manhattan between 96th Street and Chambers Street, and all stops elsewhere. During nights, they terminated at Times Square.
On May 13, 1968, 3 trains were extended to the newly completed 148th Street–Lenox Terminal. This is where the full current 3 service was formed.
After September 11, 2001, the 3 service became a local in Manhattan. After a few switching delays at 96th Street, service was changed on September 19, 2001. It ran in Manhattan as an express between Harlem–148th Street and 14th Street and was replaced by 1 service in Brooklyn. It returned to New Lots Avenue on September 15, 2002.
As a result of planned repairs to Hurricane Sandy-related damage in the Clark Street Tube, every weekend from July 2017 to July 2018, the 3 is planned to run only in Manhattan between Harlem–148th Street and Times Square–42nd Street with the 4 replacing it in Brooklyn.