hounslow3 wrote

Smallbrook Junction is similar to Friedrichstrasse, BTW, when Berlin was
divided; It was not possible to leave the station if transferring from the
U-Bahn to the S-Bahn, IIRC. Similarly at Smallbrook Junction, you can only
transfer between the Island Line and the IoW Steam Railway and
vice-versa -- there is no exit at all from the station.

Are there many other stations like that in Europe, or the world for that
matter?

Among the small number that used to exist was Killin Junction, where you
could change between the Caledonian Railway Oban line and the Killin Railway

Peter
(old enough to have changed at Killin Junction)