Which of the following is not a mode of transportation operated by SEPTA?

SEPTA, or the Southeastern Pennsylvania Transportation Authority, operates several modes of public transportation to serve the Philadelphia region. Among the traditional modes provided by SEPTA are the subway, trolley, and bus services.

The subway system in Philadelphia consists of two primary lines, known for their extensive coverage in urban areas. Trolleys, also known as streetcars, are used to connect neighborhoods with the transit network, providing local service that can navigate street-level traffic. Buses form a significant component of SEPTA’s operations, offering flexible routes that cover areas not served by rail.

In contrast, while SEPTA does operate a light rail service known as the "Regional Rail," it is distinct from light rail systems typically found in other cities. It's important to recognize that although SEPTA may utilize light rail vehicles on certain routes, the mode of transport specifically referred to as "light rail" within this context may not apply to the typical nature of SEPTA's operations. Thus, selecting light rail as the answer indicates a differentiation from the standard modes directly operated by SEPTA in their regular transit system.