T (SEPTA Metro)

The T, formerly known as the Subway–Surface Trolleys, is a light rail trolley system of the SEPTA Metro serving Philadelphia and Delaware County, Pennsylvania. The system comprises five trolley services that operate on street-level tracks in West Philadelphia and Delaware County, and also underneath Market Street in Philadelphia's Center City. The services—T1, T2, T3, T4, and T5—collectively operate on about 39.6 miles (63.7 km) of route.

Like Boston's Green Line and San Francisco's Muni Metro, the T is the descendant of a pre-World War II streetcar system. It also shares many similarities with the premetro and stadtbahn systems of continental Europe. Where Boston and San Francisco's systems use longer, articulated LRT vehicles, Philadelphia uses rigid vehicles roughly 4 feet (1,219 mm) longer than the PCC streetcar they replaced. The lines use Kawasaki Type K LRVs delivered in 1981–82. The cars are similar to those on the Media–Sharon Hill Line 100 series, SEPTA's suburban trolley routes, which were delivered around the same time. However, the T cars are single-ended and use trolley poles, while the suburban lines use double ended cars and pantographs for power collection.

In 2023, SEPTA signed a contract with Alstom for 130 new low-floor trolleys to be delivered. These cars are scheduled to be delivered from 2027 through 2030.