> I do imagine these panels must have been interactive with all the buttons?

"Spurplan" (roughly "track plan") signalling control panel. To allow a train from point A to point B, you hold down the button at A and then press B. If there's no conflicts, it will set the switches along the way, lock the route (so you can't set a route that interferes) and then "open the signal", as they say in German, at point A.

This was a customizable system built out of standard components, which served its purpose well for a long time. Point your favorite translation tool at https://de.wikipedia.org/wiki/Relaisstellwerk for more details, or http://www.stellwerke.de/ if you want to go down a rabbit hole.

> Rotte [And I believe this was a way to annotate that something was… fixed, maybe? Or on its way to being fixed?]

Rotte = work gang. Reminder tag to not send a train down there.