The station was originally served by the A train. In 1936, the A was rerouted to the IND Fulton Street Line and was replaced by E trains from the Queens Boulevard Line. In 1937, the connection to the IND Crosstown Line opened and trains were extended to Church Avenue, complementing the E. In December 1940, after the IND Sixth Avenue Line opened, E trains were replaced by the, and the GG was cut back to Smith–Ninth Streets. Following the completion of the Culver Ramp in 1954, Concourse Express trains replaced F service to Coney Island. In November 1967, the Chrystie Street Connection opened and D trains were rerouted via the Manhattan Bridge and the BMT Brighton Line to Coney Island. F trains were extended once again via the Culver Line. The station acted as a local-only station from 1968 to 1976, when F trains ran express in both directions between Bergen Street and Church Avenue during rush hours. Express service between Bergen and Church ended in 1976 due to budgetary concerns and passenger complaints. In July 2019, the MTA revealed plans to restore express service on the Culver Line between Jay Street and Church Avenue. Express service started on September 16, 2019.
Station layout
The station, located underground, has four tracks and two side platforms. The two center express tracks are at a lower level, under the local tracks, at the north end. They ramp up throughout the station to the same level by the southern end. After leaving this station, the four track line ascends onto the only original IND elevated structure. It rises above the Gowanus Canal toward Smith–Ninth Streets, the next station south. Both platforms have a green trim line on a black border and name tablets reading "CARROLL ST." in white sans-serif lettering on a black background and green border. Small directional and station signs in white lettering on a black background are below the trim line and name tablets. Large square columns painted in green run at regular intervals on both platforms with alternating ones having the standard black and white station signs.
Exits
Despite the station name, there are no entrances/exits from Carroll Street. The full-time fare control is at the extreme south end of the station. A single staircase from each platform goes up to a crossover, where a turnstile bank provides entrance/exit to the system and mosaic signs point to the platforms. The mezzanine has a token booth and one staircase to the southeast corner of Second Street and Smith Street while another staircase built inside a building leads to the northwest corner of Second Place and Smith Street. Both platforms have an un-staffed fare control area at their north ends. Each one has two exit-only turnstiles and one high entry/exit turnstile, all on platform level. The one on the northbound platform has two staircases going up to either eastern corners of Smith and President Streets while the one on the Coney Island-bound platform has one staircase going up to the northwest corner.
