"The art museums and trolleys and the mysterious fog that blanketed it. I could almost smell the cappuccinos I'd planned to drink in bohemian cafes or hear the indie music in the bookstores I would spend my free time in." ― Heather Demetrios, "I'll Meet You There"
Thanks to a man with an idea in 1869, pedestrians don't have to hike the hills, the dips and valleys of San Francisco. Andrew Smith Hallidie came up with the cable car system out west after seeing an accident involving a street car pulled by horses over wet cobblestone. The street car slid backwards and the horses were killed in the mishap.
Four years after the accident, the first street car operated by cable was introduced. What were called “Grip Cars” carried the grip that engaged the car or trolley. The engineer behind the project was William Eppelsheimer. The same engineer went on to design the Chicago Railway and London's massive Highgate Hill Cable Tramway.
As for Hallidie, he was able to patent the template for the cable car system. He basically became wealthy overnight, plus a few years. But, the next cable car system to meet San Francisco was designed by Henry Casebolt and assistant Asa Hovey, who did not want to pay Hallidie royalties for his patent. So, they came up with a newer idea that included side grips on the cars.
On a side note, the oldest cable car still in operation in San Francisco ventures up California Street. It started service in 1878.