The four New York City Subway tracks on the Manhattan Bridge, a double-decked suspension bridge that connects the New York City boroughs of Manhattan and Brooklyn, were partially closed for renovations between 1982 and 2004. This was due to severe deterioration on the bridge that resulted from one pair of tracks being more heavily used than the others.
There are two tracks on each edge of the Manhattan Bridge. The northern tracks, under the Manhattan-bound upper roadway, are on the east side of the bridge and serve the B and D trains from the IND Sixth Avenue Line. The southern tracks, under the Brooklyn-bound upper roadway, are on the west side of the bridge and serve the N and Q trains from the BMT Broadway Line. A center roadway carrying three lanes is located on the lower level and separate the two pairs of subway tracks.
The Manhattan Bridge was used by subway trains starting in the 1910s. The Broadway Line initially used the north tracks to connect to Midtown Manhattan, while the BMT Nassau Street Line used the south tracks to connect to Lower Manhattan; this was changed in 1967 with the opening of the Chrystie Street Connection, which resulted in the current service pattern. Since more traffic traveled to Midtown Manhattan, the eastern side was used more often, and the Manhattan Bridge started leaning toward its eastern side.