John, I was just doing the math myself and thinking that in fact, they may have averaged even faster than 20, if in that 3.3 hrs they stopped to take on water. How many water stops would a westbound pass. train make between Antonito and Chama or the other way around? Would they have made any other scheduled depot stops such as at Cumbres? I road both directions a few years ago and 20 would be really rockin and rollin, but I'd love to make the trip again on improved track at speed.
I bet another big benefit to improvments to track geometry would be reduced wear and tear on equipment, especially the running gear on the engines.