The Broad Street Line (BSL)—also known as the Broad Street subway (BSS), Orange Line, or Broad Line—is a subway line owned by the city of Philadelphia and operated by the Southeastern Pennsylvania Transportation Authority (SEPTA). The line runs primarily north-south from the Fern Rock Transportation Center in North Philadelphia through Center City Philadelphia to NRG station at Pattison Avenue in South Philadelphia; the latter station provides access to the stadiums and arenas for the city's major professional sports teams at the South Philadelphia Sports Complex, about a quarter mile away. It is named for Broad Street, the street under which it runs for almost its entire length. The line, which is entirely underground except for the northern terminus at Fern Rock, has four tracks in a local/express configuration from Fern Rock to Walnut-Locust and two tracks from Lombard-South to the southern terminus at NRG station. It is one of only two rapid transit lines in the SEPTA system overall alongside the Market–Frankford Line, although Center City Philadelphia is also served by four stations of the PATCO Speedline rapid transit line which runs between downtown Philadelphia through Camden, New Jersey to Lindenwold, New Jersey. With about 140,000 boardings on an average weekday, it is the second busiest route in the SEPTA system.