Regarding the 454 coming to Montrose dead in train, K-27's could not run through the Black Canon from Cimarron to Gunnison because they were too heavy for the bridges. But when repairs were needed at Gunnison they could be towed empty of water and coal to Gunnison and back.
Also, the K-27s could not run from Ridgway to Ouray for the same reason. They were used to switch the yards at Montrose and for handling heavy interchange trains between Montrose and the RGS at Ridgway. This was true both before and after the Circle was broken.