Wasn’t sure where else to put it. Does the Strom-System on the 406 have an use when you change it from DB 25kV?
Not in the game. The 406 is the ICE-3M, the M standing for Multivolt- they were built to make international runs, to Paris, Brussels, and Basel, plus Amsterdam and Rotterdam by NS, therefore they needed to be compatible with foreign electrical systems. The same is true of the 185.5 and 187, which are also multivolt. But of course so far in TSW there are no international routes.
MRCE Baureihe 185.5 change voltage system actually works what it does is actually changing the pantograph that you are using for example if you decided to use the French 25kv 50hz and Swiss 15kv 16.7hz