This is the south terminal for the train, which turns via the City Hall loop. Just north of the station are crossovers that allow trains to switch between the local and express tracks, which allow Lexington Avenue local trains to continue south via the express tracks if necessary (rather than using the City Hall loop). Due to the closure of City Hall station in 1945, Brooklyn Bridge–City Hall (which had simply been Brooklyn Bridge) became the southernmost station on normal Lexington Avenue local service.
South of the station, the downtown local track splits into three tracks. The westmost loops around to the northbound local track through City Hall station. The other two are layup tracks parallel to the downtown express track. Until the 1960s, they merged into the downtown express track north of Fulton Street, but now they are spurs ending a little north of Fulton Street, occasionally used for train storage. Plans are on the books to rejoin the layup tracks to the express track.
The station has been renovated, with new tile and ADA-compliant elevator access. It is the zero point for the IRT East Side chain; mile 0 is at the south end of the station.
The side platform on the southbound side is now home to some electrical equipment and a backup control tower for the Brooklyn Bridge interlocking, just north of the station. The tower is functional but not normally used, because the 42nd Street–Grand Central tower is the primary control point for the whole line. The interlocking board can be seen through a window along the wall along the southbound local trackway. The south end of the downtown side platform is still visible near the dispatcher's booth on the downtown island platform.
There are also some closed portions at the south ends of the existing express platforms. During the station lengthening projects it was easier to lengthen the express platform to the north. The curves at the south end proved impossible to rework so the station was lengthened northward (allowing Worth Street to be closed), and the curved southern ends of the express platform closed. Gap fillers and original mosaic tiles remain in the closed ends.
Artwork includes a 1996 work by Mark Gibian titled Cable Crossing.