Philadelphia is home to some of the most diverse public transit options in the United States. The primary transit operator in the area is the Southeastern Pennsylvania Transit Authority (SEPTA). SEPTA, the 6th largest transit operator in the US in terms of ridership, operates an extensive commuter rail system (known as the regional rail), two subway lines, trolleys (including refurbished PCC units), trackless trolleys, and one of the largest bus fleets in the country. This diversity came about as a result of the lines forming SEPTA today originally being privately owned transit companies in the past, and SEPTA’s operational organizational structure continues to reflect that history.
In addition, the Port Authority Transit Corporation (PATCO) operates a single heavy-rail line between Center City Philadelphia and Lindenwold, NJ via the Benjamin Franklin Bridge and Camden, NJ. PATCO continues to run its original rolling stock, dating back to 1968. It was one of the first transit systems in the US to use automatic train operation, and is one of the few transit lines in the nation to operate 24 hours a day, 7 days a week. Although PATCO and SEPTA do not share a fare and ticketing system, the PATCO line is shown on SEPTA maps.
The Market-Frankford Line runs east-west along Market Street and then heads north-south along Frankford Avenue. The line is elevated, except for the section in Center City Philadelphia, which is underground. The Market-Frankford Line is SEPTA's busiest, accounting for about 25 percent of the system's daily ridership each day
The subway-surface trolleys are routes 10, 11, 13, 34, and 36. They operate from a fleet of 112 SE LRV cars, manufactured by Kawasaki in 1981 and operate from the Elmwood and Callowhill Depots. The lines operate underground in Center City Philadelphia but on the surface as trolley cars in West Philadelphia.
The Suburban Trolley Division operates Route 101 from 69th Street Terminal to Media and Route 102 from 69th Street Terminal to Sharon Hill. The routes use a fleet of 29 DE LRVs manufactured by Kawasaki in 1981. While these cars appear similar to those on the Subway-Surface Lines, these are double ended and use pantographs instead of trolley poles.
The PATCO Speedline runs between Center City Philadelphia and Lindenwold, NJ via Camden, NJ. The heavy rail line is one of very few in the US to operate 24 hours a day, 7 days a week. Its fleet of railcars, originally built in the 1960s and among the first in the nation to use automatic train control, is currently being overhauled by Alstom.