Actually, on many RE routes the trains are nowadays getting fully automatically coupled/decoupled at certain places. e.g. the RE7 Kiel-Hamburg and the RE7 Flen

Actually, on many RE routes the trains are nowadays getting fully automatically coupled/decoupled at certain places. e.g. the RE7 Kiel-Hamburg and the RE7 Flensburg-Hamburg both arrive in Neumünster at the same time and are coupled together before continuing to Hamburg. It takes roughly a minute to do the coupling due to modern automated coupling solutions. On certain lines the ICE1 and ICE2 also did the same, and the IC2 is running the same rolling stock as nah.sh is using on the RE7 line, so that could also use the same technique for coupling. But this all is very expensive and complicated, and in no way worth it just for coupling a wagon with batteries to the train