Stadtbahn

You know, I was just going on a walk and I was just thinking why...

So I, I took the, the U-Bahn, which would be the metro, but it said Straßenbahn, and, uh, or Stadtbahn, sorry.

And then I know there is Straßenbahn and there is U-Bahn, and I just all of a sudden wanted to learn about it.

What's the difference and how can I, like, figure out? Is it easy to, to see? Is it the way it's, um, like, one is maybe on cables and the other one is with the tracks.