The Subway-Surface lines are remnants of the far more extensive streetcar system that developed in Philadelphia after the arrival of electric trolleys in 1892.
In October 2006, University of Pennsylvania's class of 1956 funded the construction of an innovative portal for one of the eastbound entrances of the 37th and Spruce station: a replica of a Peter Witt trolley of the kind manufactured by J. G. Brill and Company from 1923-26.