Reconstruction of the Manhattan Bridge between 1986 and 2004 disrupted N service, usually rerouting it via the Montague Street Tunnel. On April 26, 1986, the north side tracks (leading to the IND Sixth Avenue Line) were closed and services that normally ran on them were moved to the south side, running via the BMT Broadway Line. Because of the large amount of train traffic now running on those tracks, rush hour and midday N service was rerouted via the Montague Street Tunnel, making local stops in Manhattan (at all times) and Brooklyn, though evening, night and weekend trains continued to use the bridge and express tracks in Brooklyn. The , which was rerouted from the BMT Brighton Line to the BMT West End Line, replaced the N as the weekday express on the Fourth Avenue Line.