Sometimes, a poster is just a poster and not an indication of anything. There were 2 separate steam loco posters on 2 routes and not come to tsw.
That one is a known train simulator Classic route basically it's much cheaper for the development team to Simply bring in an existing TSC route like that one to the game some of the German routes started like this
Whatever are you targeting that post reunification or communist German Democratic Republic Deutschen Demokratischen Republik era
Never travelled on the real thing (sadly) but there are versions in both MSTS and Trainz. I also bought the cab ride Blu-ray and it is a magnificent journey. In response to Mr Woods, I would think post unification the most practical and politically correct era to do. Of course the “L” part of the LAMP process would be key to whether or not the route could be an official DLC. Mind, with the editor coming out, there’s nothing to stop someone making the route or something based on it, standard gauge with a 363 or G6 hauling N-wagons up there.
If you have Arosa, there should be a track with 1m width that is also used in the Harz. Would probably not look exactly accurate but it would be more accurate than standard gauge. They actually have waggons that transport normal gauge freight waggons. Nowadays, there isn't that much freight anymore but a bit remains.
Those 99 Class steam locos are magnificent. Riding the Harz lines is definitely one on my bucket list!