>>1101666I think Karlsruhe is the only one that really fits the definition in the OP.
There are a lot of cases that meet some criteria, but are different concepts.
- Stadtbahn (no streetrunning in city centers, almost full grade separation) like Köln/Bonn or Düsseldorf
- Tram-Train in Kassel or Chemnitz, uses diesel-electric hybrid vehicles
-Überlandstraßenbahn in Halle, Dresden or Gotha with regular streetcars
Historically though there have been more examples though, as there were tons of electric Kleinbahnen that were separate from normal city-wide streetcar systems. They usually linked smaller communities with each other or a bigger city, and had both freight and passenger service. Most of them were owned by public authorities and sometimes managed by private contractors. A good example is the Kleinbahn Wesel-Rees-Emmerich.
