Powell Street is a shared Muni Metro and Bay Area Rapid Transit station near the intersection of Market Street and Powell Street in downtown San Francisco. The station is located along the Market Street Subway and extends underground from Fourth Street to Fifth Street. Hallidie Plaza connects to the station on the north side of Market Street. Like all of the shared BART and Muni stations on the Market Street Subway, the concourse mezzanine is on the first level down, an island platform for the Muni Metro is on the second level down, and the island platform for BART is on the third level down. The Powell-Mason and Powell-Hyde cable car lines turn around at Powell and Market, above the station.Service at this station began on November 5, 1973., Powell Street was the busiest station in the BART system. At this and other downtown stations, passengers may resort to “back-riding” during the evening commute across the bay. They take a train in the other direction for a few stops and then transfer to the correct train at a station when the train is less crowded such as Glen Park.The under-construction Central Subway must dive deep underground to pass underneath this station. The Central Subway will include a new station on Stockton Street between Union Square and Market Street, to be connected by a tunnel to the existing Powell Street station mezzanine. The result will be a single integrated underground complex running all the way from Union Square to Market and Fifth Streets.