Broad Street Line

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, under which the line runs for almost its entire length. In 2024, as part of the SEPTA Metro plan, the Broad Street Line is expected to be renamed the B Line.

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, though Center City Philadelphia is also served by four stations of the PATCO Speedline rapid transit line which runs from Center City Philadelphia through Camden, New Jersey to Lindenwold, New Jersey. With about 115,000 boardings on an average weekday in 2019, it is the second busiest route in the SEPTA system.

The line and its trains were leased to SEPTA in 1968 after it assumed operation of the city transit systems from the former Philadelphia Transportation Company (PTC). Broad Street Line subway cars bear both the SEPTA logo and the seal of the City of Philadelphia to reflect the split ownership-operation arrangement.