What is the physics behind cable cars?

The theory, and reality, is that a balanced number of cars make for very little actual work for the cable drive motor. The weight of the cable is self balancing as are the cars. Most of the work comes from overcoming the friction, and shear inertia of the system.

Why was the cable car important?

As cable cars appeared in cities around the world, people were most interested in their ability to replace horse-drawn vehicles. However, cable cars were also better able to climb hills, an important quality in hilly San Francisco!

What is the difference between a street car and a cable car?

But, there’s a simple test to distinguish streetcars from cable cars: If it runs on steel rails with a trolley pole connected to an overhead wire above, it’s a streetcar. If it runs on steel rails with an open slot between them, and no overhead wires, it’s a cable car.

How does a cable car work?

How Cable Cars grip and let go of the Cable. The cable car’s grip – essentially a 300-pound-plus pair of pliers – extends through a slot between the rails and grabs hold of the cable to pull the car along.

What happens to the cable when you cross the road?

There’s no problem for the upper cable, as the car just continues as normal. For the lower cable (typically the line that was built at a later date), as the car approaches the crossing the gripman releases the car’s hold on the cable, which is pulled down by one or more pulleys.

How does the let-go/drift curve work?

In the first, the “let-go” or “drift” curve, the grip person simply releases the cable to let the car coast around the corner. Once the car is around the corner, the cable can be taken up again.

How do cable channels move?

A system of pulleys supporting the cables from below allows the cables to move in the channels. At the end of a line, the cable is turned by a large pulley called a sheave (pronounced “shiv”). Cable channels can be seen from the Museum Sheave Room.