SEPTA Metro consists of twelve lines containing thirteen trains; The L and B, both of which were inherited from the former Philadelphia Transportation Company, and originally built by the Philadelphia Rapid Transit Company.
It also includes the M, an interurban rail line between Norristown, Pennsylvania and Upper Darby Township, Pennsylvania, originally owned by the Philadelphia and Western Railroad, then acquired by the Philadelphia Suburban Transportation Company (PSTC).
The five T line branches and the single G line were inherited from the former Philadelphia Transportation Company (PTC) and originally built by the Philadelphia Rapid Transit Company (PRT).
The two D line branches were built by the Philadelphia and West Chester Traction Company (P&WCTC) and later inherited by the Philadelphia Suburban Transportation Company (PSTC).
Moved to current location in 1989 as part of integration with then new Norristown Transportation Center Various extension and infill stations with platforms will be added to the D and T trolley lines as part of SEPTA's Trolley Modernization Plan.