K-37 class 493 walks the tightrope through the Animas River Canyon with train 464 back to Durango. K-37s were the largest of the narrow gauge 2-8-2s and pre-D&SNG were not allowed to operate on the Silverton Branch. 493 and 497 (traded to C&TS in 1991 for K-36 482) are the only two K-37 class engines to operate this section of narrow gauge trackage.