stations except 5th Street were reopened in June 2020. In 2021, SEPTA proposed rebranding their rail transit service as "SEPTA Metro", in order to make the system easier to navigate. Under this proposal, services along the Market–Frankford Line will be rebranded as the "L" lines with a blue color. Each service would receive a suffix, with local service becoming the L1 Market–Frankford Local. Operation As with many other rail lines, the signal system on the Market–Frankford Line has progressed from the original lineside block signals using semaphores, to three-aspect Type D color light (green, over yellow, over red) signals, to cab signalling, eliminating the lineside block signals except at interlockings. The Market-Frankford line is unusual as subway–elevated systems go. Notable features include being built with Pennsylvania trolley gauge of , and in its use of bottom-contact or underrunning third rail. As such, any possible future physical connection to other rapid-transit lines in Philadelphia is limited to cross-platform transfer only, as both the Broad Street subway and the Norristown High-Speed Line are standard gauge () with top-contact third rail. The Market–Frankford Line and Metro-North Railroad are the only railroads in North America that use bottom-contact third rail, known as the Wilgus-Sprague system. Its advantages include a reduced risk of electrocution for track workers and fewer disruptions due to icing conditions during winter weather. The Market–Frankford Elevated's original construction also had some marked differences from that of other US elevated systems (such as Chicago or New York City). While those systems' elevated lines were built with rails laid on ties (sleepers) that were bolted directly to large steel girders, the Market-Frankford's structure consisted of steel girders supporting a concrete trough deck, which then supported the more conventional railroad construction of rails laid on floating ties with loose rock ballast. This was done in an attempt to reduce noise and vibration, as well as protect the streets below from rain and "operational fluids." Prior to February 2020, during rush hours SEPTA operated trains in a skip-stop pattern. Stations were designated as "A" stations, "B" stations, or "All Trains" stations; trains designated as "A" trains skipped "B" stops and vice versa. Skip-stop service ended on February 21, 2020, and was replaced by expanded all-stations service three days later. The base fare for riding the line is $2.00 using the Travel Wallet on a SEPTA Key card and $2.50 using a Quick Trip. Payment of