MonoMonday:Origins

Thanks Nickimags888 for hosting this month.

I think this would qualify as the origins of the San Francisco cable car system, the only functioning one in the world these days.
These enormous wheels are powered by electricity (originally by steam) and pull the cables which run under the streets.
The cable cars grip the cable and are pulled along at 9.5 mph.

You can see this actual powerhouse, centre of the entire system, at the cable car museum which we visited this morning.
I expected it to be rather dry and more of interest to Mr isbi but I found it really fascinating.

We are now about to leave for the airport to start our trip home.