I'd love to see the gap on the Rhine route closed and this is the missing part. Then we'd have a closed network starting from Trier-Koblenz or Düsseldorf-Köln-Koblenz via Frankfurt, Mannheim, Karlsruhe, Offenburg, Freiburg to Basel. (Even with the Höllental branch starting from Freiburg) As this is only 40 miles / 64 km it could be released as an extension to either Freiburg-Basel or Strasbourg-Karlsruhe.
Also nice to have would be the scenic mountaineous Murgtal route from Rastatt to Freudenstadt. It has been done before for MSTS (ProTrain 16 - Schwarzwaldromantik) with branches to Herrenalb and Ittersbach and Karlsruhe. (Still playing that on OpenRails as I've travelled this route a lot in RL) Rolling stock would be a DUEWAG/Siemens GT8-100D (3 and 6 cars) and the Prussian G12 (BR 58) which is still in service pulling special sightseeing trains. https://en.wikipedia.org/wiki/Murg_Valley_Railway
Interesting idea, though I don't think DTG treats a route as an extension nowadays, instead selling at full price with the original attached. So provided it's treated as an extension, I like the idea.
Bad Bf is enough , While Basel SBB would also be nice. MSTS has the full route Karlsruhe-Basel (ProTrain 12 Addon). Enjoying this on OpenRails, also Murg Valley where I lived for 20 years (Gaggenau & Gernsbach)
Excellent Idea and this should form a merged route Koblenz Frankfurt to Basel with this route linking the Karlshule Strasbourg Offenburg to the Freiburg Basel Railway. This mirrors the OBB Nightjet 402/403 routing the Amsterdam Duisburg Dusseldorf Koln Koblenz Frankfurt to Zurich via Basel Freiburg. Locomotives here should be DB BR185.1 185.0 ICE 4 ICE 1 with Swiss Pantograph SBB Rabe 503
Wholly agree with this idea, had a run up this route for the first time just last week, in a Siemens desiro HC (after a run behind a V36 on the Sauschwänzlebahn). The only problem I can foresee would be rolling stock, the ICEs and 101s on the Intercity and TRAXXs on freight services would be easy enough, however from what I could see, most regional services were in the hands of Desiro HCs and Class 463 Mireos, neither of which currently exist in game. Would absolutely love to see one made though!