Concourse-Central Park West-6 Av-West End Express
The D train operates between 205 Street in the Bronx and Coney Island in Brooklyn 24 hours a day via the Concourse Express (peak direction rush hours only, otherwise local) in the Bronx, the Central Park West and 6 Avenue Express tracks (24 hours a day, only express train service to operate overnight) in Manhattan and the 4 Avenue Express tracks (late nights via local) in Brooklyn and via the West End Line to Coney Island.
The D train is one of the IND 6 Avenue Subway routes that began operating with the opening of the Sixth Avenue Subway on December 15, 1940, running from 205 Street in the Bronx to Hudson Terminal (now the World Trade Center Station). Just like today trains run express in the Bronx during peak direction rush hours only as it does today and express in Manhattan 24 hours-a-day.
C and CC trains had provided all service along the Concourse Line previously, with C trains sharing the middle track along the Concourse Line during rush hours until 1949 (when the C Express train was discontinued, increasing D train frequencies) with CC service becoming the Concourse line local route running during rush hours only, allowing D trains to run express.
D trains were extended to Coney Island, replacing F trains as the Brooklyn 6 Avenue line service, when the Culver Ramp opened in 1954. Since 1954 D trains have serviced Coney Island basically continuously to this day except for the route trains have taken to Coney Island has changed with trains operating along every route in regular service except the Sea Beach Line.
Trains operated from 1967 until 2001 via the Brighton Line in Brooklyn, although from 1968 through 1986 all rush hour and later all weekday daytime trains terminated at Brighton Beach as the D train ran express along the Brighton Line (and express trains need to terminate at Brighton Beach because otherwise there is switch congestion). Late nights and Weekend service still ran through to Coney Island.
D train service to Brooklyn was wholly discontinued from 2001 to 2004 when the north side of the Manhattan Bridge had to be closed for rebuilding. The closure of the north 6 Avenue side of the Manhattan Bridge also happened before, between 1986 and 1988 but a special Yellow D train operating between 57 Street and Coney Island (route of today’s pre-Second Avenue Subway, Q train) with Orange D service running from 34 Street to 205 Street, the same service pattern as from 2001 to 2004.
The north side of the Manhattan Bridge opened again in 2004. This allowed service along both sides of the Manhattan Bridge to resume after 18 years of one side or the other side being closed for reconstruction. For these service changes, the D train underwent a radical shift in service with Broadway Line Q trains remaining as the full time Brighton Line service, B trains (already weekdays only in Northern Manhattan) matched to become the Brighton Line express weekday only service. Finally, the D train resumed service to Coney Island but was re-routed to become the West End Line service via the 4th Avenue Express (the B trains routing until 2001). This is how the D train operates to this day. The new D train service routing also gave the West End Line 24-hour service to Manhattan instead of just late-night shuttle service. This meant all 4 routes between Coney Island into Manhattan (via the lines named after original surface railroads) got 24 hour service for the first time.
For rolling stock D trains presently use R68 subway cars based out of Concourse Yard that have operated on the D train since they were launch subway route for the cars in 1986.
