D (SEPTA Metro)

The D, formerly known as the Media–Sharon Hill Line (MSHL) and numbered 101 and 102 (to Media and to Sharon Hill, respectively), is a light rail line in the SEPTA Metro network serving portions of Delaware County, Pennsylvania. The line comprises two services which terminate at 69th Street Transit Center in Upper Darby Township, Pennsylvania: D1 to Media and D2 to Sharon Hill. Service is operated by the Suburban Transit Division of the Southeastern Pennsylvania Transportation Authority (SEPTA). Altogether, the two services operate on approximately 11.9 miles (19.2 km) of route. The line is one of the few remaining interurban systems in the United States, along with the South Shore Line in Illinois and Indiana, the River Line in New Jersey, and the M, also in the Philadelphia area.

Along with the M, formerly the Philadelphia and Western Railroad, the routes are the remaining lines of the Red Arrow Lines Trolley System once operated by the Philadelphia Suburban Transportation Company (successor to the Philadelphia and West Chester Traction Company); some local residents still call them "Red Arrow".

The line uses 29 Kawasaki Heavy Industries Rolling Stock Company Type K LRV cars similar to those used on the T. However, unlike the city cars, the Type K cars on the D1 and D2 are double-ended and use pantograph collection instead of trolley poles.