The Queens Boulevard Line is a fully underground line of the New York City Subway, as part of the division. The line provides an east-west connection across Manhattan at 53rd Street and east through Queens to Jamaica. The part in Manhattan was once known as the 53rd Street Line. Except west of Queens Plaza , the line is quadruple-tracked, with express service on the inner tracks. It is also one of two lines (the IND Culver Line being the other) that has a shorter path for the express tracks than the local tracks. It is the second busiest line in the system, the busiest being the IRT Lexington Avenue Line.
The following services use part or all of the Queens Boulevard Line:
service
section of line
express (local late nights)
west of Briarwood (some rush hour trips use the full line)
local east and express west of Forest Hills
east of split east of Queens Plaza
local (no service rush hours or middays)
Forest Hills to Queens Plaza
local (no service late nights)
Forest Hills to Queens Plaza
local (no service late nights or weekends)
Forest Hills to Fifth Avenue
The Queens Boulevard Line begins at Jamaica-179th Street as a four-track subway under Hillside Avenue . Just after curving north under the Van Wyck Expressway, a flying junction joins the recent two-track IND Archer Avenue Line () to the local and express tracks. Soon after, the line turns west under Queens Boulevard.
East of Kew Gardens-Union Turnpike , another flying junction ties the eastward tracks to Jamaica Yard . The other side of the wye curves west to become a lower level of the subway just west of Kew Gardens-Union Turnpike. After passing through 75th Avenue , those tracks join the local and express tracks with another flying junction. Just west of there is Forest Hills-71st Avenue , where several services () begin on the local tracks, and service switches to the express tracks.
After a while, the subway leaves Queens Boulevard for Broadway. At the Northern Boulevard intersection, the express tracks head west on Northern Boulevard, while the local tracks take a longer route, staying on Broadway and turning south on Steinway Street to rejoin the express tracks. As the line approaches Queens Plaza , the new two-track IND 63rd Street Line () splits from both sets of tracks at a flying junction (providing an extra two tracks into Manhattan). The Queens Boulevard Line continues under Northern Boulevard to Queens Plaza , where tracks allow V service to switch to the express tracks. Just after Queens Plaza, the line splits into three parts at yet another flying junction. The express tracks continue on towards Manhattan, while the local tracks split two ways, with the 60th Street Tunnel Connection () turning northwest and the Crosstown Line () turning southwest. From this point on, the Queens Boulevard Line has only two tracks.
The line continues west through the 53rd Street Tunnel under the East River into Manhattan. After a station at Lexington Avenue-53rd Street , the westbound tracks rise above the eastbound tracks. A flying junction after Fifth Avenue-53rd Street ties the Queens-bound tracks into the downtown-bound local tracks of the Sixth Avenue Line (), which begin here as a merge of these connection tracks and the IND 63rd Street Line (). At that junction, the Sixth Avenue Line turns west under 53rd Street, just to the south of the Queens Boulevard Line. The two lines share platforms at Seventh Avenue, but no connecting tracks are present. Then the Queens Boulevard Line turns south below the Eighth Avenue Line () with separate platforms at 50th Street , and then the tracks split to join the local and express tracks of the Eighth Avenue Line north of 42nd Street-Port Authority Bus Terminal . At that station, a special unused lower platform serves a single southbound track from the Queens Boulevard Line, merging with both southbound tracks of the Eighth Avenue Line south of that station. It has been speculated that this platform and level was built to prevent the from extending their Flushing Line west.