The Centre Street subway carried four tracks from a point just west of the former Essex Street terminal of the BMT Broadway Elevated in Brooklyn to Canal Street, where the two center tracks terminated. Just south of that station, the Nassau Street Loop tracks entered from the bridge, providing four tracks again through Chambers Street. Just south of Chambers Street, the two center tracks end. Original plans called for the two west tracks, coming from the Jamaica Line, to rise onto the Brooklyn Bridge as part of the Centre Street Loop. The Nassau Street Line continues south as a two-track subway to the Montague Street Tunnel, where it merges with the BMT Broadway Line.