These monorail systems can be seen in most cities. They work by using large clockwork springs and utilise compressed air or steam stations along the line to rewind them. They are quite popular as they don’t produce smoke. These light railways often cling to the sides of buildings.
However, the rail companies that run these are notorious for running them on a low budget and not maintaining them very well. Every now and then a spring will break and either the carriage will explode, or it will be pinged away some distance. The Flying Scotsman and The Scarborough Flyer are two services renowned for their frequent aerodynamic exploits.