I knew it was inevitable that crashes were likely on this route. So far only managed to complete one timetable and one scenario. I expected the game to crash around Frankfurt because of it's enormity but no. Instead I crash either just after Hanau (still just as expected) if I'm Frankfurt bound or (and this is the surprise) in the middle of nowhere between the end of the LZB section and Fulda if I'm Fulda bound. Furthest I got so far was just before the end of the long single track tunnel heading to Fulda with an ICE-T with all gen 8 layers. Usually with other routes crashes are usually in the same place, like Dresden Mitte. Hence why the crashes only heading Fulda bound in the what I assume is the least memory intensive areas, are a surprise. Maybe it is dynamic weather? Will try again. Apart from that route is really fun to drive and I like going in and out of LZB and GNT monitored zones.
I think this might actually just be down to you playing on an 8th gen console. I'm on PS5 and even I run into the occasional crash on this route, though I haven't properly tried it since all the optimisations went out. Point being, if even a 9th gen console struggles with the route and runs out of memory, an 8th gen probably shouldn't even have it in the first place.
I'm not surprised that I'm getting crashes, I fully expect on gen 8 I'm surprised at where on the route they are happening. I expected to never be able to go anywhere near Frankfurt Hbf because of the amount of track, the size of the station and all the scenery of the city, but so far I haven't had a crash anywhere near Frankfurt.