Cable Car Museum: 'moving museum' gag

The San Francisco Cable Car Museum houses the original winding wheels, engines, and historic cars that power and display the city's cable car system; the power house equipment on display still drives the cables under the streets. Admission to the museum is free and it documents the mechanical workings behind the operational cable car lines that run nearby. Because riders share the historic vehicles that are preserved and explained inside the museum, locals often joke that the cable cars are 'moving museums' as well as functioning public transit. The museum is situated at the base of the Powell–Mason and Powell–Hyde lines.