The Second Avenue Subway (internally referred to as the IND Second Avenue Line by the MTA and abbreviated to SAS) is a New York City Subway line which runs under Second Avenue on the East Side of Manhattan. The first phase of this new line, with three new stations on Manhattan's Upper East Side, opened on January 1, 2017. The full Second Avenue Line (if funded) will be built in three more phases to eventually connect Harlem–125th Street in East Harlem to Hanover Square in Lower Manhattan. The proposed full line would be and 19 stations long, serve a projected 724,000 daily riders, and cost more than $24.7 billion.
The line was originally proposed in 1920 as part of a massive expansion of what would become the Independent Subway System (IND). In anticipation of the Second Avenue Subway being built to replace them, parallel elevated lines along Second Avenue and Third Avenue were demolished in 1942 and 1955, respectively, despite several factors causing plans for the Second Avenue Subway to be cancelled. Construction on the line began in 1972 as part of the Program for Action. It was halted in 1975 because of the city's fiscal crisis, leaving only a few short segments of tunnels completed. Work on the line restarted in April 2007 following the development of a financially secure construction plan. The first phase of the line, consisting of the 96th Street, 86th Street and 72nd Street stations, as well as of tunnel, cost $4.45 billion. A , $6 billion second phase from 96th to 125th Streets began construction in June 2026.
Phase 1 is served by the Q train at all times and limited rush-hour N and R trains. Phase 2 will extend the line's northern terminus from 96th Street to Harlem–125th Street. Both the Q and limited N services will be extended to 125th Street. Phase 3 will extend the line south from 72nd Street to Houston Street in Manhattan's Lower East Side. Upon completion, a new T train will serve the entire line from Harlem to Houston Street. Phase 4 will again extend the line south from Houston Street to Hanover Square, maintaining the T designation for the entire line. The T's route emblem will be , the color assigned to services that use the Second Avenue Line through Midtown Manhattan.
Extent and service Services that use the Second Avenue Line through Midtown Manhattan are to be colored . The following services use part or all of the Second Avenue Line:
Time period Section of line Rush hour (limited service) Phase 1 All times Rush hour (one northbound trip)
Phase 1 Phase 1 of the Second Avenue Line opened in January 2017. It runs under Manhattan's Second Avenue from 65th Street to 105th Street, with stations at 72nd Street, 86th Street, and 96th Street. It is double-tracked along its entire length, with tracks in parallel tubes bored by tunnel boring machines, and central island platforms at all stations. North of 96th Street, both tracks continue as storage tracks until they end at 105th Street.
As part of Phase 1, the Second Avenue Subway connects to the BMT Broadway Line using an existing connection via the 63rd Street Line. The Q, as well as limited rush-hour N and R, operates northward from 57th Street–Seventh Avenue on the Broadway Line, curving east under Central Park on the 63rd Street Line. Broadway Line trains then stop at Lexington Avenue–63rd Street with a cross-platform interchange to the train before merging with the Second Avenue Line near 65th Street. This connection also connects to the Sixth Avenue Line allowing for trains from the Sixth Avenue line to access the Second Avenue Subway, though this connection has been unused in regular service . The northbound 63rd Street Connector track dips below the level of Phase 3's planned tunnels, providing for a future flying junction between the connector and the rest of the Second Avenue Line.
Plans for expansion The long-term plans for the Second Avenue Subway involve digging of new tunnels north to Harlem–125th Street in Harlem and south to Hanover Square in the Financial District of Lower Manhattan. The entire line would also be double-tracked, except for a tentatively four-tracked segment between 21st and 9th Streets, including the 14th Street station, with the outer two tracks used to store trains. After Phase 4 is completed, the residents of East Harlem and the Upper East Side will have mass transit service down both Second Avenue and Broadway to the Financial District (the latter via transfer to Broadway local trains), as well as across the Manhattan Bridge to Brooklyn via the Q train.
An additional two-track connection is planned at around 63rd Street that will connect the Lower Manhattan-bound tracks on the Second Avenue Line with the Queens-bound tracks on the IND 63rd Street Line, using existing bellmouths at 63rd Street and First Avenue. Current plans do not call for it to be used by regular service. Instead, it would be used for moving out-of-service trains. The connection would allow for trains to run from the Financial District to Queens if the capacity of the IND Queens Boulevard Line were increased, or if the Queens Bypass were built.
Service from Queens via the 63rd Street Tunnel would allow for the full capacity of the line south of 63rd Street to be used. The whole line will be designed to accommodate 30 trains per hour, with the exception of the terminal at Hanover Square, which will only be able to handle 26 trains per hour (TPH). The portion north of 63rd Street is planned to have 14 TPH on the Q and 14 TPH on the T, for a combined 28 trains per hour on both routes. South of there, only 14 TPH on the T are planned, although 12 additional TPH could be provided in the future via the 63rd Street Tunnel. The 2004 plans for the Second Avenue Subway include the construction of short track segments to allow a future extension north under Second Avenue past 125th Street to the Bronx, as well as an extension south to Brooklyn.
In order to store the 330 additional subway cars needed for the operation of the line, storage tracks would be built between 21st Street and 9th Street along the main alignment. The 36th–38th Street Yard in Sunset Park, Brooklyn, would also be reconfigured.
The Second Avenue Subway is chained as "S". The track map in the 2004 FEIS showed that all stations, except for 125th Street, would have two tracks and one island platform. 72nd Street and 125th Street were conceived as three-track, two-platform stations. 72nd Street was eventually scaled down to a two-track, center island platform station in order to reduce costs, A three-tracked 72nd Street station would have allowed trains from the Broadway Line to short-turn (reverse) without interfering with mainline service on Second Avenue, as well as provided additional operational flexibility for construction work and non-revenue moves. In July 2018, the 125th Street station was also scaled down to a two-track, one-platform station because the MTA had ascertained that two-tracked terminals would be sufficient to handle train capacities, and that building a third track would have caused unnecessary impacts to surrounding buildings.
History
Initial attempts
After World War I, the New York City Subway experienced a surge in ridership. By 1920, 1.3 billion annual passengers were riding the subway, compared to 523 million annual riders just seven years before the war. In 1919, the New York Public Service Commission launched a study at the behest of engineer Daniel L. Turner to determine what improvements were needed in the city's public transport system. Turner's final paper, titled Proposed Comprehensive Rapid Transit System, was a massive plan calling for new routes under almost every north-south Manhattan avenue, extensions to lines in Brooklyn and Queens, and several crossings of the Narrows to Staten Island. Among the plans was a massive trunk line under Second Avenue consisting of at least six tracks and numerous branches throughout Brooklyn, Queens, and the Bronx. The Second and Third Avenue elevated lines were to be knocked down to make room for the 6-track subway. The paper was revised in January 1927.
In September 1929, the Board of Transportation of the City of New York (BOT) tentatively approved the expansion, which included a Second Avenue Line with a projected construction cost of $98.9 million (equivalent to $ in ), not counting land acquisition. In the north, several spur lines in the Bronx would merge into a four-track trunk line, crossing the Harlem River south to 125th Street. There would be six tracks from 125th Street to a link with the IND Sixth Avenue Line at 61st Street, then four tracks from 61st Street to Chambers Street, and two tracks from Chambers Street to Pine Street.
The Great Depression began that year and the soaring costs of the expansion became unmanageable. Construction on the first phase of the IND was already behind schedule, and the city and state were no longer able to provide funding. In 1930, the line was scaled down, with the line from 125th to Houston Streets to be complete by 1940, as well as a spur along 34th Street to be done by 1948. This scaled-down plan was postponed in 1931. In 1932, the Board of Transportation modified the plan to further reduce costs, omitting a branch in the Bronx, and truncating the line's southern terminus to the Nassau Street Loop.
Further revision of the plan and more studies followed. By 1939, construction had been postponed indefinitely, with only a short length being completed above the Second Avenue station. The Second Avenue Line was relegated to "proposed" status, and was number 14 on the Board of Transportation's list of important transportation projects. The line was cut to two tracks with single northern branch through Throggs Neck, Bronx, a connection to the BMT Broadway Line in Manhattan, and a continuation south onto the IND Fulton Street Line in Brooklyn via that line's Court Street station. The subway's projected cost went up to US$249 million (equivalent to $ in ). The United States' entry into World War II in 1941 halted all but the most urgent public works projects, delaying the Second Avenue Line once again.
As part of the unification of the three subway companies that comprised the New York City Subway in 1940, elevated lines were being shut down all over the city and replaced by subways. The northern half of the Second Avenue Elevated, serving the Upper East Side and East Harlem, closed on June 11, 1940. The southern half, running through Lower Manhattan, East Midtown and across the Queensboro Bridge to Queens, closed on June 13, 1942. The demolition of the Second Avenue elevated caused overcrowding on the Astoria and Flushing Lines in Queens, which no longer had direct service to Manhattan's far East Side. The elevated line's closure, as well as a corresponding increase in the East Side's population, increased the need for a Second Avenue subway.
In 1944, BOT superintendent Philip E. Pheifer put forth a proposal for Second Avenue Subway services, which would branch extensively off to B Division. The subway was originally to be opened by 1951, but in 1945, plans for the Second Avenue Subway were again revised. Another plan was put forth in 1947 by Colonel Sidney H. Bingham, a city planner and former Interborough Rapid Transit Company (IRT) engineer. O'Dwyer and Gross believed that construction of a Second Avenue subway line would be vital to both increasing capacity on existing lines and allowing new branch lines to be built. Bingham's proposal involved more branch lines and track connections than did Phiefer's, and similar to the 1960s and 1990s phased proposals, was to be built in sections. In 1948, New York City was short $145 million of the $800 million program needed for rehabilitation and proposed capital improvements. The City petitioned the New York State Legislature to exceed its $655 million debt ceiling so that the city could spend $500 million on subway construction, but this request was denied.