[10][11][12][13][14] The station was placed at 21st Street, serving the Queensbridge Houses to the west, and commercial and industrial buildings to the east.

As early as 1976, the Program for Action had been reduced to seven stations on the Archer Avenue and 63rd Street lines and was not projected to be complete for another decade.

[18][19] Usage estimates for the 21st Street–Queensbridge station were calculated in 1984 at 220 passengers per hour unless a connection was made to the rest of the system.

[20] The MTA voted in 1984 to connect the tunnel to the local tracks of the IND Queens Boulevard Line at a cost of $222 million.

The project included repairing the platforms and stairways, adding lighting, fixing the canopy above the main entrance, and renovating employee rooms.

Above this is a thin black strip of metal and above this are yellow squares that take the platform walls up to the station ceiling that is made of concrete.

[13][39] As with other stations constructed as part of the Program for Action, the 21st Street–Queensbridge station contained technologically advanced features such as air-cooling, noise insulation, CCTV monitors, public announcement systems, electronic platform signage, and escalator and elevator entrances.

This is an inefficient terminal setup,[8] requiring passengers to know which track the next train will depart from before going to the platform level.

As a terminal from 1989 to 2001, the station had tail tracks that continued eastward as far as 29th Street, ending at bumper blocks.

[44][51][48] The current bellmouth, built along with the Queens Boulevard connection, is two levels deep with two additional stub-end subway tracks named T1A and T2A.

[54] Just above the connection sits the 29th Street Ventilation Complex, built with the connector, in the site of a former parking lot.

[45][48][49] West of the station, a second ventilation complex lies in Queensbridge Park between Vernon Boulevard and the East River.