1873: Andrew Hallidie tests the first cable car in San Francisco.

Hallidie is said to have conceived his idea in 1869 while watching a team of horses being whipped as they struggled to pull a car up wet cobblestones on Nob Hill. They slipped and were dragged to their deaths.

It so happened that Hallidie’s father held the British patent for wire-rope cable, and when the son came to the Gold Rush fields he put it to use hauling ore-laden cars from mines. So it wasn’t too much of a stretch for him to envision horseless cable cars carrying passengers up the steep slopes of San Francisco’s hills.

He...