From the NY Times:
Cutting-edge train technology is coming to the No. 7 train, the purple-hued line that runs between 42nd Street in Manhattan and Flushing, Queens.
A computerized signal system, which basically allows trains to drive themselves (although this has not yet happened in the New York subway) will be rolled out on the No. 7 line by the end of 2012. Only the L line currently uses the system, which uses radio waves to track train movement.
In theory, the signals obviate the need for a conductor or train operator, although the transit union has bitterly opposed the elimination of on-board personnel. The system, known as Communications Based Train Control, also allows trains to run more frequently, increasing capacity during rush hours.
New York City Transit is looking to spend $87 million on cars for the No. 7 line conversion. Next up will be the Queens Boulevard tracks, which would serve the E, F, M, and R lines, followed by the Culver line in Brooklyn to Coney Island, which serves F and G trains. About $577 million is earmarked for the technology over the next five years.
Graphic from the NY Post