switching to the local track north of 34th Street to serve the Astoria Line. Instead, it skipped 49th Street and terminated at 57th Street. When the north side of the Manhattan Bridge reopened on December 11, 1988, the south side of the bridge was closed. B, D, and Q trains were rerouted from the Broadway Line to the Sixth Avenue Line using the north side of the bridge. The N began running local in Manhattan and via the Montague Tunnel at all times. In order to replace B service to Ditmars Boulevard, additional N service was provided during rush hours. On September 30, 1990, express service on the Broadway Line was restored when repair work on the Manhattan Bridge was temporarily suspended. The N then began making express stops from 34th Street to Canal Street at all times except late nights. R service between Manhattan and Brooklyn was increased during rush hours. During late nights, R trains no longer ran via the Broadway Line; instead, they operated as a shuttle in Brooklyn, terminating at 36th Street. The brief Broadway service via the Manhattan Bridge was stopped on December 27 because of a cracked beam on the bridge. From April 30, 1995 to November 12, 1995, the Manhattan Bridge services were supposed to go back to the 1986–1988 service pattern with only the south side Broadway Line tracks in service. However, the Broadway side was not yet ready. As a result, during middays and weekends, the north side of the bridge was also closed. As a result, Q trains began serving the Broadway Line again. They ran via the Montague Street Tunnel, before switching to the express tracks after Canal Street. This service continued past 57th Street via the BMT 63rd Street Line to 21st Street–Queensbridge, being the first scheduled service to use this connection. On February 22, 1998, construction on the IND 63rd Street Line cut B and Q service to 57th Street–Sixth Avenue. Service on the 63rd Street Line was replaced by a shuttle running from the BMT Broadway Line. Trains originally operated from 57th Street–Seventh Avenue to 21st Street–Queensbridge, with 20-minute headways. On April 6, 1998, because the service did not terminate at an ADA-accessible station, the shuttle was extended to 34th Street–Herald Square on weekdays, skipping 49th Street via the express tracks. Normal service resumed on May 22, 1999. 2001–present The current set of four services —