HOW CABLE CARS WORK
Condensed version

Much of the attraction of San Francisco's surviving cables cars is due to the antique nature of the cars and the seemingly mysterious method by which they travel up and down the steep hills and grades of the City. Most of that is true of the system itself as well; just how the little cars run has fascinated locals and tourists alike who, like Rudyard Kipling in the 1890s, marvel at cars gliding on their tracks, apparently without any visible means of propulsion. Yet the system is amazing simple in many ways and all the more remarkable in that it has changed little since the first cable car lines appeared in Victorian San Francisco of the late 19th century.

Andrew Hallidie is considered the father of the cable car, although he was not the only inventor to dabble in the use of cable as a means of transportation. Hallidie and his father both held several patents for the manufacture and use of cable, or wire rope as it was called.
Each of the different cable car lines once had its own powerhouse, or sometimes several, to drive the cable used on the line. The first power sources were steam engines powered by enormous amounts of coal each day, thus each powerhouse was equipped with boilers to heat the water needed to produce steam.

How
Cable Cars
Work