[4] The D operates 24 hours a day between 205th Street in Norwood, Bronx, and Stillwell Avenue in Coney Island, Brooklyn.

During rush hours in the peak direction, D service makes express stops between Fordham Road in the Bronx and 145th Street in Manhattan.

During rush hours in the peak direction, the D also runs express between Fordham Road in the Bronx and 145th Street in Manhattan.

[11] Between October 7, 1957, and 1959, four rush hour trains ran to Euclid Avenue via the IND Fulton Street Line when the D started being inspected at Pitkin Yard.

In conjunction with this project, the new express tracks on the Sixth Avenue Line between West Fourth Street–Washington Square and 34th Street were opened, providing additional capacity for the extra trains on the IND via the connection.

The D replaced Q service, which had run local in Brooklyn (except during morning rush hours and early evenings) and express on the BMT Broadway Line in Manhattan, terminating at 57th Street.

Late morning and early afternoon D trains would from then on run express from Brighton Beach to Kings Highway.

The northern section ran between Norwood–205th Street in the Bronx and 34th Street–Herald Square (the orange D) while the southern section ran express on the BMT Broadway Line from 57th Street–Seventh Avenue to Canal Street, then crossed the south tracks of the Manhattan Bridge into Brooklyn, and operated local along the Brighton Line to Stillwell Avenue (the yellow D).

[22] At this time, the local tracks on the BMT Brighton Line also underwent reconstruction, necessitating the suspension of express service.

During late nights and weekends, D trains ran express between Prospect Park and Kings Highway depending on which tracks were being worked on.

[24] By 1987, as reconstruction on the Brighton Line progressed, the weekday skip-stop pattern expanded to Prospect Park, with D trains serving Beverley Road while Q trains served Cortelyou Road and Parkside Avenue, with Church Avenue as a mutual station.

[26] On December 11, 1988, the north tracks of the Manhattan Bridge reopened and the two sections of the D joined together running via Sixth Avenue Express.

[29] From April 30 to November 12, 1995,[30] the Bridge's north tracks closed during middays and weekends and during these hours, D service was cut south of 34th Street-Herald Square.

[37] From May 24, 2004, to fall 2004, signal modernization on the IND Concourse Line required the suspension of D express service in the Bronx.

[38] From September 18, 2021, until January 24, 2022,[39] southbound D trains terminated at Bay 50th Street so work could be completed to protect Coney Island Yard from flooding.