I could well imagine the route Magdeburg - köthen - Halle - Halle/Leipzig Airport - Leipzig Messe - Leipzig Hbf. Because we already have a large part of the layer. Br 146.0 Br 146.5 Dbpbzfa Br 114 Br 143 Br 112 Br 1442 Br 442 Trains you could add: Br 412 Lint 41/42. Then you would have this route and for route hopping you could use Rapid Transit where you can then change in Leipzig Messe or in the main station. With the ICE/IC, a journey takes 1 hour and 20 minutes on the complete route, where you would have to take the RE 30 from Magdeburg to Halle and from there as S3/S5(X) Continue to Leipzig.
