Cable car truck

According to the museum, "Each cable car is supported by two trucks that carry all the grip mechanisms, wheels, brakes, support frame, and wooden body of the car.

"The truck alone, without the wooden body, could travel the rails. The body merely provides shelter and seating for the riders as well as creating the look of the car. The truck and body together weigh about 6 tons."

This is a standard Muni truck, but in the early days of cable cars, from 1880 to 1906, there were nine companies operating 22 cable car lines in San Francisco. Each operator utilized different track gauges in order to prevent the other operators from using their lines. That meant each truck had different widths. Muni standardized the system in 1956.