Ninth Avenue is a bi-level express station on the BMT West End Line of the New York City Subway, located at the intersection of Ninth Avenue and 39th Street in Brooklyn. Each level has three tracks and two island platforms. The upper level serves the BMT West End Line while the lower level formerly served the BMT Culver Line. Only the upper level is still in service and is served by the D train at all times. The center express track is not normally used.
The station house is at street level and there is a sealed entrance on the west side. The tablet grilles in the mezzanine are still intact and a newsstand once stood opposite the current location of the station agent booth. On the upper level, the Manhattan
-bound platform is slightly wider than the Coney Island
-bound platform. Towards the west end of the upper level platforms is an employee-only pedestrian bridge that leads to the entrance of the 36th–38th Street Yard via a high turnstile.
Beyond the ramps, as the line curves under the BMT Fourth Avenue Line, there are tracks that continue straight into the piers on the waterfront, which were once operated by the South Brooklyn Railway. In the tunnel approaching 36th Street station, there is an unused trackway that was supposed to connect to the South Brooklyn Railway. The tunnel connection was never built. This trackway merges to the southbound track and runs for a long distance before ending at a wall.
As of 2010, the Coney Island-bound platform has been renovated with new platform edges, a new dispatcher room and a new stairway that leads to the 36 Street yard.
The lower level was used as a through route for the BMT Culver Line to the BMT Fourth Avenue subway and the BMT Fifth Avenue elevated lines until 1954, when service on the main portion of the BMT Culver Line route was recaptured by the Independent Subway System via the Culver Ramp. A Culver Shuttle service from this station to a new single track terminal at Ditmas Avenue was begun at the same time. Some Culver trains continued to operate into Manhattan until May 1959. Culver Shuttle service was discontinued on May 11, 1975.