Tunneling for Second Avenue Subway Continues

After completing the excavation of the first of two tunnels earlier this year, a Tunnel Boring Machine (TBM) has begun mining the second (east) tunnel for the Second Avenue Subway. Starting again from 92nd Street, this second tunnel will be 7,800 linear feet long.

On its journey, the second tunnel will make a tight, westerly curve into the existing 63rd Street Station. Once completed, the tunnel will receive the concrete lining which provides the permanent tunnel structure.

During the first 200 feet, the TBM will be mining through ground which has been frozen, a technique which engineers employ to harden soil, or decomposed rock, enabling the excavation process.

The TBM previously mined 7,162 feet for the first tunnel. The 485-ton, 450-foot-long machine began mining in June 2010 from 92nd Street to 65th Street and was then disassembled and pulled back to 92nd Street where it started its second run on the second tunnel last week. The subway line is on schedule to be completed by December 2016.

Phase I of the Second Avenue Subway will serve more than 200,000 people per day, reducing overcrowding on the Lexington Avenue Line and restoring a transit link to a neighborhood that lost the Second Avenue Elevated in 1940.When Phase I is complete, it will decrease crowding on the adjacent Lexington Avenue Line by as much as 13%, or 23,500 fewer riders on an average weekday. It will also reduce travel times by up to 10 minutes or more (up to 27%) for those on the far east side or those traveling from the east side to west midtown.

The line is being built in phases, with Phase I providing service from 96th Street to 63rd Street as an extension of the Q train, with three new ADA-accessible stations at 96th, 86th and 72nd Streets. New entrances to the existing Lexington Av/63 Street Station will also be added at 63rd Street and Third Avenue. Further phases of the project will extend the line from 125th Street in Harlem to Hanover Square in the Financial District. The configuration of the tracks will allow for possible future extensions into Brooklyn, Queens, and the Bronx.

The Second Avenue Subway is one of four large-scale projects being built as the MTA undertakes the largest expansion of New York's public transportation system in two generations. The MTA is also connecting the Long Island Rail Road to Grand Central Terminal, extending the 7 subway line to the far west side, and building the Fulton Street Transit Center in Lower Manhattan.