Never heard of it, but that doesn’t mean that you’re wrong, of course.
Let me correct myself, in the germanspeaking area of europe this is a relatively new invention, as said, in Karlsruhe they did it, atleast in Germany, for the first time with Trams equipped for two powering systems, one for the normal train tracks which use a higher voltage than the tram tracks and one for the tram tracks inside the cities.
Thus the border between trams and “normal” trains is liquid, they move in the cities and for Intercitytravel they move onto the train tracks of the German Federal Railway, the Deutsche Bahn, and act as commuter trains.
I guess, in Switzerland this is maybe more unknown than here in Germany, but I don’t know, logically thought, since Trams got more power in their motors than busses, the Swiss people must be using them more often than we Germans do because of their mountanious terrain and cities and villages, but thats just a guess, I don’t have any official numbers at my disposal to prove this.
A little offtopic:
On this picture you see a tramstation of the “Karlsruher Stadtbahn”, in the background you can see a regional train of the Deutsche Bahn and a ramp with tracks leading from the tram towards the regular tracks.
To be honest, I grew up in the region, thus my fascination especially for this tram-train-system, childhood memories you know ^^