The D Sixth Avenue Express is a service of the New York City Subway. It is colored orange on the route sign (either on the front and/or side - depending on equipment used) and on station signs and the NYC Subway map, as it represents a service provided on the IND Sixth Avenue Line through Manhattan. Its normal service pattern is from Norwood–205th Street in the Bronx to Coney Island-Stillwell Avenue, running local in the Bronx and express in Manhattan and northern Brooklyn. During rush hours, service north of 145th Street is express in the peak direction (and the B is extended to serve local stops), and during late nights, only Manhattan service is express.
The Template:NYCS DD designation was only used once, in December 1962, during a water main break at Sixth Avenue and 18th Street. It ran local between 205th Street and Stillwell Avenue, making all stops, using the IND Eighth Avenue Line north of West Fourth Street, and the IND Sixth Avenue Line south.
On November 26, 1967, the IND Chrystie Street Connection opened, adding express service on the Sixth Avenue Line and connecting it with the Manhattan Bridge. D service was switched over to BMT Brighton Line via this new connector. It became the express service on weekdays to Brighton Beach and the local to Stillwell Avenue other times. In Manhattan, it ran express from West Fourth Street to 34th Street rush hours only (the B used the express tracks to terminate there at other times). It would become the full time Sixth Avenue Express when non-rush hours B service was extended to 57th Street-Sixth Avenue.
When the north side of the Manhattan Bridge was closed in 1986, D service ran in two sections, one between the Bronx and 34th Street while the other ran from 57th Street on the BMT Broadway Line, then express along the Broadway Line to Canal Street, then over the south side of the Manhattan Bridge into Brooklyn, and then along the Brighton Line to Stillwell Avenue. At this time, D/Qskip-stop service ran in Brooklyn on weekdays.
In 1988, the north side reopened and the two sections joined. The D now ran as the full time Brighton Local to Stillwell Avenue.
In May 1995, the north side was closed during midday and weekends and D service was cut south of 34th Street. On July 22, 2001, it was closed at all times and D service was cut again. In Brooklyn, it was replaced by Q local service.
After September 11, 2001, C service was suspended. On weekends, the D ran local on the Eighth Avenue Line north of 59th Street to fill in the gap caused by the suspension.
On February 22, 2004, the north side of the Manhattan Bridge was reopened, and D trains were extended via the north side of the bridge to Brooklyn, replacing the W as the Fourth Avenue Express (late nights local) and West End Local to Stillwell Avenue.
From May 24 to Fall 2004, construction on the IND Concourse Line suspended D express service in the Bronx, but the B still traveled to Bedford Park Boulevard during rush hours.
The Eighth Avenue fire in January 2005 caused D trains to run local on the Eighth Avenue Line north of 59th Street on weekday evenings until C service was restored on February 2.