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 that 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 and when it will be funded, will be built in three more phases to eventually connect Harlem–125th Street in Harlem to Hanover Square in Lower Manhattan. The proposed full line would be and 16 stations long, serve a projected 560,000 daily riders, and cost more than $17 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 is in planning .
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 will be colored since it will 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:
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.