Editing Market Frankford Line (section)

== History ==

The Market Street Elevated opened in 1907, providing rapid transit service above Market Street through Center City and West Philadelphia to 69th Street. The line used elevated structure west of City Hall, with plans for eventual subway construction through Center City. This elevated operation established the route that would become the Market-Frankford Line.<ref name="septa"/>

The Market Street Subway opened in 1908, placing the Center City portion underground while maintaining the western elevated section. The combination of subway and elevated operation in a single line created the configuration that persists today. Eastern extension on the Frankford Elevated opened in stages, reaching Frankford in 1922 and completing the line's current route.<ref name="septa"/>

The line operated under various transit agencies before SEPTA assumed control in 1968. Major rehabilitation projects have rebuilt stations, replaced cars, and modernized systems while maintaining the historic route. The current fleet of Bombardier M-4 cars entered service beginning in 1997, replacing earlier equipment dating to the 1960s.<ref name="septa"/>