At 1201 Mason St. is one of the city's best free stops, and it's a working piece of infrastructure.

Inside the powerhouse

The museum shares a building with the cable car power house and car barn. From two galleries, you can look down on the motors and winding wheels that drive the cables. Signs over each one, reading "Hyde," "California," "Mason" and "Powell," show which line it pulls. You can also go down below the corner of Washington and Mason to see the cavern where the cables turn on huge sheaves before heading out under the streets.

The cars

The collection includes Clay Street Hill Railroad grip car No. 8, the only surviving car from the first cable car company, and Sutter Street Railway grip car 46 and trailer 54 from the 1870s.

The history

The museum opened in 1974 and is run by the Friends of the Cable Car Museum, a nonprofit. Its exhibits cover the system from the first run in 1873 to the near-loss of the cable cars and the 1982-84 rebuild.

Visiting

Admission is free. The museum says it is open daily except Mondays. The Powell-Mason and Powell-Hyde lines stop nearby.