Mainz has a real train station.
Trains come in at one end and go out the other.
Not like Frankfurt or Wiesbaden.
There, trains come in, stop and somehow get magically turned around before they can leave. Definitely sub-standard places.
Here's an ICE heading across the Rhine from Wiesbaden.
Could be going backwards, for all I can tell.
(That would save them having to turn it around, I suppose)