The process for the CHS to become involved in the preservation of an historic structure and subsequent funding through the grant process is pretty well laid out, and has been for years. It starts with the owner of the property, local governmental and historical societies, etc., well before the drop dead situation of demolition. In the case of the Alamosa roundhouse, I would assume the city never designated it as a local historic structure, a relatively simple procedure, but it has to be initiated by someone, and the local historical society, if there is one, needs to have motivated people to push it along, etc. Alamosa appears to have ignored its railroad heritage except for the engine on display and the B-1.
Another program that produces results is the Colorado Preservation Inc program of Colorado's Most Endangered structures/sites program. The Antonito depot is on this year's list of nominations, and the "winners" will be announced at the CPI conference in Denver in February. There are several avenues that work in Colorado for historic preservation, but it takes a lot more than a knee jerk phone call or letter to someone at CHS. Anyone can make a nomination to CPI's list, but it often goes begging for input. They have a web site--discover the system and put it to use--we do that here in Silverton. I am a site reviewer for this program for CPI and see the process from the inside.