SAS meaning in Governmental ?

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 is 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 8.5 miles (13.7 km) 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 finally began in 1972 as part of the Program for Action, but 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 1.8 mi (2.9 km) of tunnel, cost $4.45 billion. A 1.5-mile (2.4 km), $6 billion second phase from 96th to 125th Streets is in planning and is expected to open by 2027–2029.

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, and 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 turquoise since it will use the Second Avenue Line through Midtown Manhattan.