TP has three advantages: 1. it is by far the shortest, most direct route to Texas, where the oil will be going for refining; 2. It doesn't go through any major metro areas, unlike the Moffat route through Denver, or west to SLC and then east on the original UP and then back south through Denver; 3. It doesn't go near Denver's water supply, as the Moffat does for around 30 miles, literally feet away for most of that route on the east side of the tunnel.

My parents (and grandparents and great grandparents before them) live around 100' away from both the Moffat route and South Boulder Creek, Denver's main water supply, most of which comes through the original pioneer bore of the Moffat Tunnel from the west slope. They live around two miles from where in 1991 a manifest hit a rock slide, and the engines and several cars slid down into South Boulder Canyon, killing the head end crew, and dumping several loads of lumber and the fuel from the engines into the creek, a steep 100' below. Can you imagine if that had been a loaded petroleum train? It would have dumped into Gross Reservoir long before anyone could get up there on foot, polluting a big chunk of Denver's water for decades to come.

Now, UP is a common carrier with federal preemption for its activity, but the State can make things miserable for them if it wants to, and I am sure UP knows that. If I were to bet I would say the most likely scenario is back through Wyoming on the original UP, which is the fastest route believe it or not to Denver, even if it is longer. If TP does reopen, I would bet that UP does it, not RGP.