These railroads all terminated in Camden, where passengers could catch ferries across the Delaware River to Philadelphia.
Early in the 20th century, the idea of a fixed Delaware River crossing connecting Camden and Philadelphia gained traction, and in 1919, the states of Pennsylvania and New Jersey formed the Delaware River Bridge Joint Commission to build a bridge between the two cities.
The Delaware River Bridge (now Ben Franklin Bridge) was designed to accommodate rail as well as road traffic; when it opened on July 1, 1926, it had two outboard structures beside the main roadway for rail and space for two streetcar tracks (never installed) on the main road deck.
Construction of the rail line did not actually begin until 1932, and the Bridge Line opened on June 7, 1936.
Relatively short, it only had four stations: 8th Street and Franklin Square in Philadelphia (the latter currently closed) and City Hall and Broadway in Camden (connecting to the Pennsylvania-Reading Seashore Lines at Broadway).