The Chestnut Street Subway, first proposed by A. Meritt Taylor in 1913 remained a proposed route into the 1920s. In 1923, the Philadelphia Department of Transit proposed a bridge at Chestnut Street in West Philadelphia across the Schuylkill and then into Chestnut Street as a subway at 21st Street. The tunnel would provide two tracks for surface trolleys plus a moving platform system for local traffic. The trolleys would connect to the West Philadelphia trolley network at 42nd Street and head east to at least 7th Street where they would turn towards the Delaware River Bridge and take passengers to Camden, NJ. A branch would also continue down Chestnut Street to a point near Independence Square or to the Delaware Avenue and its ferry services.
The moving platforms were the most novel part of this plan. Touted “as the next stage in transit development,” a series of moving platforms would hustle walkers from point to point, a level above the trolleys or trains. The platforms (what we might call conveyor belts today) would run at 3 miles per hour, 6 MPH and 9 MPH. The fastest track would have seats for the ride.
The moving platforms were imagined to run from 32nd Street, past the proposed new Pennsylvania Station at 30th Street (in 1923 the station was to be set between Chestnut and Market Streets) across the Schuylkill River and then to a terminus either at Independence Hall or near Delaware Avenue.
The moving platforms concept dates to the late 1890s and was actually put into practice at the World’s Columbian Exposition in Chicago in 1893 and at the Paris Exposition Universelle in 1900. New York had similar proposals for 42nd Street and a loop that would connect the Brooklyn, Manhattan, and Williamsburg bridges in Manhattan.
The Moving Walkways of Chestnut Street [The Necessity of Ruins]