Pier 43 is a vestige of the San Francisco Belt Railroad, which served many waterfront docks and once operated dual-gauge tracks. At its height, it operated 67 miles of trackage and served Southern Pacific (from the south end of the line by the current CalTrain terminal) and Northwestern Pacific, Western Pacific and AT&SF from the piers. The lines were largely paved over when the modern Embarcadero was laid. However, San Francisco made up for it a bit by acquiring and operating a fleet of heritage PCC Streetcars!
