Click here to download a map. In 1984, Port Authority began operating a 25-mile light rail system, called the T, which provides service to Downtown Pittsburgh and several communities south of the city. Four light rail transit lines to the South Hills -- Allentown, South Hills Village, Overbrook and Library -- currently provide thousands of people with convenient and efficient transit service to Downtown Pittsburgh and other destinations in southern Allegheny County each day.                                                                           The Authority’s newest light rail line, the Overbrook Line, reopened on June 2, 2004 and provides quick rail service from Castle Shannon to Downtown Pittsburgh. The 5.2-mile Overbrook Line, was closed in 1993 due to trackbed deterioration, has been upgraded to modern light rail standards as part of the Stage II Light Rail Transit Project. The T also winds through Downtown Pittsburgh via a subway with three underground stations (Steel Plaza, Wood Street and Gateway, which is currently closed for reconstruction) and an above-ground station at First Avenue. The subway provides rail service to major destination points and business centers within Downtown Pittsburgh. The southern end of the T, between South Hills Village and Castle Shannon, opened in April 1984. The downtown subway opened on July 1985, and modernization of the line between South Hills Junction and Castle Shannon was completed in May 1987. Work is currently underway on a light rail construction project, called the North Shore Connector, that will extend the T by 1.2 miles.