 The MTA 's final environmental impact statement was approved in April 2004 ; this latest proposal is for a two @-@ track line from 125th Street and Lexington Avenue in Harlem , down Second Avenue to Hanover Square in the Financial District . The new subway line will actually carry two services . The full @-@ length Second Avenue line , extending from Harlem to the Financial District , is to be given the color turquoise and the letter designation T. However , a rerouted Q , the line 's other service , will begin carrying passengers first . The MTA plan calls for building the Second Avenue Subway in four segments with connections to other subway lines . The first segment ( Phase One ) is a proposed reroute of the Q , the Broadway Express via the BMT 63rd Street Line and north along Second Avenue to the Upper East Side at 96th Street . Phase Two will extend the rerouted Q train to 125th Street . In Phase Three , the new T train will run from 125th Street to Houston Street . The final phase will extend T train service from Houston Street to Hanover Square in Lower Manhattan . Track maps on the MTA 's website show that all stations , except for 125th Street , will have two tracks and one island platform . ( 72nd Street was conceived as a three @-@ track , two @-@ platform station , as is 125th Street . However , the 72nd Street station is being constructed with two tracks and one platform . ) 
