A point not mentioned is that 168 took $500,000 to restore. A K-36 or K-37 will take $800,000 to $1,000,000, at least. That's a big difference in cost. Will talked about how only five is needed but I visited Chama a few short weeks after there was a locomotive shortage for a week or so. 488 was still being rebuilt and two K-36 locomotives went down for repairs. That left 463 and a K-36 to run the schedule. There were significant delays because 463 had to turn at Osier to stay on the Antonito side. They likelihood of a locomotive undergoing a rebuild and two K-36 locomotives being down at the same time is marginal but does illustrate the point that it would be nice to have another in operation. During a computer transition, I unfortunately didn't back up some of my research on this but I *believe* that I calculated that after the initial restoration another locomotive could spread out the rebuild cycle enough that it wouldn't cost anymore than it does now as far as 1472 and running gear rebuilds. After six locomotives the numbers go the other way if I'm remembering correctly.
Fact is the guys in charge know what they are doing and how to achieve those goals. I'm sure if money existed and they already expanded the shop and got all the passenger cars rebuilt they'd love to have a sixth locomotive.