I would totally buy this. If made, the route should include UP, SP, and/or ATSF (or BNSF) diesels or maybe even some SP steam later on. The Tehachapi Loop at Walong, California is pretty famous. The trains actually go over or under themselves.
Worth mentioning: https://forums.dovetailgames.com/th...the-november-survey-discussion-i-guess.15376/ It's on this list, meaning that DTG has at least had the idea, but of course that doesn't automatically mean they're making it. I agree though, this would be a great route for TSW. Some detail on the proposal would be nice, though.