IND Sixth Avenue Line

Extent and service

The following services currently use part or all of the Sixth Avenue Line, whose services' bullets are colored bright orange:

The majority of the Sixth Avenue Line has four tracks, two local and two express. At each end, these pairs of tracks split, giving the line two north and two south ends. One of the north ends is at 57th Street, where two tracks lead south under Sixth Avenue from the IND 63rd Street Line (used by the F train at all times). The other is just south of 59th Street–Columbus Circle, where a two-track line splits from the IND Eighth Avenue Line at a flying junction (with connections to the local and express tracks), immediately turns east under 53rd Street, and crosses the IND Queens Boulevard Line, which parallels it just to the north. At Seventh Avenue, the southbound track is above the northbound track (the same is true on the Queens Boulevard Line, though north is the opposite direction from the Sixth Avenue Line). These tracks are used by the B and D express trains.

This line then turns south to go under Sixth Avenue, merging with the branch from 57th Street and a connection to the IND Queens Boulevard Line (used by the M train) to become a four-track line. The southbound track becomes the westernmost track, and the northbound track becomes the second track from the east; the other lines merge to become the second track from the west and the easternmost track, with connections only between the 63rd Street Line and the two main tracks. After passing through 47th–50th Streets–Rockefeller Center, the two southbound tracks cross; the main tracks become the two center express tracks and the tracks from the other lines are the two outside local tracks.

South of 42nd Street–Bryant Park is a large interlocking with many crossovers and switches. The original express tracks ended just to the south at 34th Street–Herald Square and some services switched to the local tracks at the interlocking. This was done because the PATH tunnels already existed under Sixth Avenue south of 33rd Street and the Sixth Avenue Line local tracks were built on each side of PATH. The section between West Fourth Street–Washington Square and 34th Street–Herald Square, the only express section of this line, was originally built as a two track subway with the provision to expand to four tracks later (the express tracks were added in the 1960s during the Chrystie Street Connection projects). As a result, they are placed under the local tracks and PATH using the deep-bore tunneling method.

At West Fourth Street–Washington Square, the express tracks return to the same level as the local tracks. A flying junction just to the south connects the local tracks of the Eighth Avenue Line. The Sixth Avenue Line then turns east under Houston Street. After Broadway–Lafayette Street, the express tracks turn south and use the Chrystie Street Connection to Grand Street before crossing the north side of the Manhattan Bridge into Brooklyn. The express tracks used to continue on to the express tracks at Second Avenue before the tracks were rerouted to the Chrystie Street Connection. The local tracks split at this point. One pair continues east to Second Avenue (used by the F train) while the other pair merges with the BMT Nassau Street Line at Essex Street (used by the M train).

Just before approaching Second Avenue, the line splits into four tracks again. The two express tracks, currently not used in revenue service, continue east and dead-end. They would have entered Brooklyn merging with the never-built IND Worth Street Line. The local tracks in Manhattan turn south under Essex Street and Rutgers Street before crossing under the East River via the Rutgers Street Tunnel to become the IND Culver Line in Brooklyn, stopping at the outer tracks of Jay Street–MetroTech.

Construction and opening

The IND Sixth Avenue Line was built to replace the elevated IRT Sixth Avenue Line, which was closed and demolished in 1939. The first portion of the line to open was the part not under Sixth Avenue. What was then known as the Houston–Essex Street Line began operations at noon on January 1, 1936 with two local tracks from a junction with the Washington Heights, Eighth Avenue and Church Street Line (Eighth Avenue Line) south of West Fourth Street–Washington Square east under Houston Street and south under Essex Street to a temporary terminal at East Broadway. E trains, which ran from Jackson Heights, Queens to Hudson Terminal, were shifted to the new line to East Broadway. Two express tracks were built on the portion under Houston Street until Essex Street-Avenue A; the tracks were intended to travel under the East River and connect with the never-built IND Worth Street Line in Williamsburg, Brooklyn.

Just after midnight on April 9, 1936, trains began running under the East River via the Rutgers Street Tunnel, which connected the Houston-Essex Street Line with the north end of the Jay–Smith–Ninth Street Line at a junction with the Eighth Avenue Line north of Jay Street–Borough Hall. E trains were sent through the connection to Church Avenue. Simultaneously, the Fulton Street Line was opened to Rockaway Avenue and the A and C trains, which had used Smith Street, were rerouted to Fulton Street.

At first the city intended to take over the Hudson and Manhattan Railroad (PATH) tunnel in Sixth Avenue for express tracks at a future time, building a new subway at a lower level for the H&M.

On March 23, 1936, Mayor LaGuardia broke ground for a new Sixth Avenue subway at Bryant Park in order to replace the Sixth Avenue Elevated and to complete the Independent Subway System. $4,000,000 was spent in order to underpin the Sixth Avenue Elevated during construction.

On December 15, 1940, local subway service began on Sixth Avenue from the West Fourth Street subway station to the 47-50th Street subway station with track connections to the IND 53rd Street Line. The Sixth Avenue Line's construction cost $59,500,000. The following routes were added with the opening of service:

Sixth Avenue express tracks and the Chrystie Street Connection

Ground was broken for two new express tracks between the West Fourth Street and 34th Street–Herald Square stations on April 19, 1961. The express tracks were built eighty feet beneath the surface. The construction was done in two portions. The first section was between West 9th Street and West 19th Street, and the second section was between West 19th Street and West 31st Street. The express tracks were part of a major subway improvement program that began with the reconstruction of the DeKalb Avenue station in Brooklyn. The second phase of construction, was the Chrystie Street Connection, which would connect the BMT lines coming over the Manhattan Bridge and the Williamsburg Bridge with the IND Houston Street Line. The express tracks, and the construction of a two-track spur line between West 52nd Street and West 58th Street with a new terminal at 57th Street would allow the necessary capacity for the trains to operate. Construction on the section between West 9th Street and West 19th Street began in early 1961, but work was halted by a water main break, and with other delays the work was only twenty percent complete in July 1963. Construction on the section between West 19th Street and West 31st Street started in the middle of 1961, and was 60 percent complete in July 1963. The first section was 88 percent complete on June 30, 1965, and the second section was 99 percent complete on that date. Between West 55th Street and West 58th Street, a third of the structural work was done by this date. No stations were constructed along the new express tracks, but provisions were incorporated into the design of the tunnel to permit the addition of future lower level stations at 14th Street and 23rd Street without disturbances to train operation.

On November 26, 1967, the first part of the Chrystie Street Connection opened and Sixth Avenue Line express tracks opened from 34th Street–Herald Square to West Fourth Street–Washington Square. With the opening of the connection to the Manhattan Bridge, BB service was renamed B and it was extended via the new express tracks and the connection to the West End Line in Brooklyn. D service was routed via the connection and onto the Brighton Line instead of via the Culver Line. It only ran express during rush hours. F service was extended from Broadway–Lafayette Street during rush hours, and from 34th Street during other times to Coney Island via the Culver Line. On July 1, 1968, the 57th Street station opened and the portion of the Chrystie Street Connection connecting the line with the Williamsburg Bridge was opened. Service on the KK was inaugurated, running from 57th Street to 168th Street on the BMT Jamaica Line. B service was extended during non-rush hours from West Fourth Street to 57th Street. D trains began running express via the Sixth Avenue Line at all times.

Planning for the connection to the IND Queens Boulevard Line began in December 1990, with the final design contract awarded in December 1992. Construction began on September 22, 1994. The remaining section from 21st Street to the Queens Boulevard Line cost $645 million. In December 2000, the 63rd Street Connector was opened for construction reroutes. The Connector came into regular use on December 16, 2001 with the rerouting of F service at all times to 63rd Street. The construction project also extended the lower level LIRR tunnel and involved a number of other elements, including the integration of ventilation plants, lowering a sewer siphon 50 feet, rehabilitation of elements of the existing line, mitigating ground water, diverting trains which continued to run through the project area and widening of the entry point to the Queens Boulevard Line to six tracks. This new tunnel connection allowed rerouting the Queens Boulevard Line F trains via the 63rd Street Tunnel, which increased capacity on the heavily-travelled Queens Boulevard Line. It also allowed a new local service, the V train, to run along the Sixth Avenue and Queens Boulevard lines; this service has since been discontinued and replaced with an extension of the M train.

Manhattan Bridge closure and the opening of the 63rd Street Line

The stubs that were eventually used for the IND 63rd Street Line were built for a proposed extension under Central Park to Harlem.

Between 1988 and 2001, the Manhattan Bridge south tracks were closed for reconstruction, and the short-turn local was replaced with a part-time express to Brooklyn, the Q train.

On December 16, 2001, a new service, the V, was introduced operating local via Sixth Avenue and terminating in the center tracks of the Second Avenue station. The V only operated during weekdays. At this time, the F was rerouted to operate via the IND 63rd Street Line instead of the IND 53rd Street Line after leaving the 47th–50th Streets–Rockefeller Center station. On June 28, 2010, the V was replaced by the M, which began using the Chrystie Street Connection to the Williamsburg Bridge, being the first service to use that connection in revenue service since the K in 1976. The M makes all former V stops except for the Second Avenue stop.