I agree with El Coke, and would add a couple of things. First, I think the "group dynamic" of the C&TS, SLRG, and D&S is real and has potential. Last Saturday, I rode the SLRG (a delightful ride, too). The next day, not even really looking for them, I counted at least four people that were on the SLRG train on Saturday riding the C&TS on Sunday.
Second, I think the economic impact of the C&Ts on the local economy is underestimated. I would guess that at least half of the restaurant and lodging business in Chama is tied to the C&TS. I think there are indirect impacts that people don't think about. For example, I know several people who got to know the area that surrounds the C&TS because they came there to ride the train. They subsequently returned there to hunt, fish, snowmobile, etc. I doubt that kind of economic benefit is counted in the benefits attributed to the C&TS. Of course, the local employment that the C&TS provides multiplies through the rest of the local economy.
Third, I think one of the most important long-term things that can be done to ensure the C&TS's survival is the protection of the atmosphere and environment that the C&TS traverses. The C&TS doesn't need any more recreational and second home development along its route to mar the authentic experience of riding through unspoiled country. If people want to ride through 20 miles of recreational suburbia on a train, they can go to Durango.
What makes the C&TS such a national treasure is that in almost no other place in America is it possible to ride an authentic steam train over a route in which the countryside has changed little in 75 years. That entire experience exemplifies the term "living museum" better than most any other historical attraction in the country that I can think of. It's too bad that the C&TS can not get more national recognition (and funding) for that reason alone.