I don’t know how they worked out the timetable for Arosa. Random number generator maybe? It’s not like there are a huge number of trains on the route (there may be more services we can’t see yet, planned for a DLC). How long it takes to get from one station to the next seems to be guessed at best, as some are not physically possible. It may just be down to poor AI behaviour and it’s been tweaked out of all proportion just to keep the AI trains or dispatcher from getting confused.
Rivet launched IOW without timetables and now they do this? I have a hard time deciding which situation is worse.