Well, this railway doesn't have the extreme slopes I showed here three weeks ago. I think it is the oldest railway I have ever seen, and some of its track is still in situ. One of my photos shows points. It doesn't seem to have rusted because the track is made of granite slabs rather than iron/steel. It was built before the invention of the steam locomotive, and is therefore called a tramway rather than a railway. Horse‑drawn carts transported granite from a nearby quarry, which was used for building particularly in London. Of course London is 250 miles away.
A bit over 30 miles from Plymouth. It runs/ran from Haytor to Teigngrace. It is almost all downhill at a constant gradient from Haytor, so for about 99% of the line, the horses would only have to drag the empty wagons uphill. From Teigngrace there was a short canal to Newton Abbot whence the granite was transported to London by ship.
When we visited, it was June and there were some teenaged schoolchildren there, obviously on a field trip. One of the boys found some leeches in the water which has filled the old quarry, and seemed quite disappointed that the beasts didn't suck him dry. Most leeches in this country have mouthparts too small to bite people. Only the medicinal leech and the horseleech can bite through mammalian skin. There were also newts in the water.
I dont know if they count as railway or not... But back in San Francisco, there are "Cable cars". The tracks contain a hollow slit and below them, there are moving cables. The driver simply has to move a crank that grips the cable causing the car to move. San Francisco has a lot of slopes !!