The Wuppertaler Schwebebahn (English: Wuppertal Suspension Railway) is a suspension railway in Wuppertal, Germany. The line was originally called the German: Einschienige Hängebahn System Eugen Langen (English: Eugen Langen Monorail Overhead Conveyor System) named for its inventor, Eugen Langen. It is the oldest electric elevated railway with hanging cars in the world and is a unique system in Germany.
https://www.cnn.com/travel/article/wuppertal-schwebebahn-suspension-railway-germany/index.html
I’d imagine the ride would be smoother since they really only need to level between each support, not the entirety of the rails if they’d been laid on the ground.
Yes, it is really smooth. As you get on at the station the car tends to swing from side to side just a little bit. This reminds you that it’s suspended from the top, not sitting on rails. More cities should have these!