The Paoli/Thorndale Line, commonly known as the Main Line, is a SEPTA Regional Rail service running from Center City Philadelphia through Montgomery County
both ends, as well as some with only a single cab. These cars use the standardgauge of 4 ft 8+1⁄2 in (1,435 mm). The Market–Frankford Line uses a class
Amtrak and SEPTA's Philadelphia-to-Harrisburg main line, which hosts SEPTA's Paoli/Thorndale Line commuter rail service, and Amtrak's Keystone Service and
Philadelphia Technical System length 78 mi (126 km) Track gauge 4 ft 8+1⁄2 in (1,435 mm) standardgauge 5 ft 2+1⁄2 in (1,588 mm) Pennsylvania trolley gauge