By the late 1920’s, the Rio Grande Southern Railroad (operating between Durango and Ridgway) had upgraded its track to accept larger and heavier locomotives. The necessarily frugal railroad had realized the need to lease some of the Mudhens to maintain their operation. By this time, the Denver & Rio Grande Western (as it was re-named during company reorganization in 1921) was able to expend some of the K-27’s for use on the “Southern”. At one time or another, most of the Mudhens had a turn at pulling the diminutive trains through the grandeur of southwestern Colorado on the RGS.

In 1939, the RGS finalized the trade of ditcher 030 to the D&RGW in exchange for engine 455. All was not well for long however. In November of 1943, the 455 was badly wrecked as its heavily loaded manifest lost air braking ability on the north side of Dallas Divide, a mere 11 miles from its destination at Ridgway. The engine crew on board had jumped to relative safety, but the ill-fated engine and train picked up excessive speed and turned over on a curve south of the siding at Valley View.

While operating under the auspices of the Department of Defense, the RGS rebuilt the 455 at Ridgway (returning it to service in April of 1947) and managed to squeeze a few more good years out of her. The “new” 455 sported a rebuilt standard gauge cab (from D&RGW 0-6-0 #60) and a very different looking tender tank acquired from D&RGW 2-8-0 #933. The instability of this retro-fitted tank resulted in the railroad borrowing the tender from the 452 and coupling it with the 455 toward the end of its career. The engine lasted until the end of RGS operations and fell to the scrapper’s torch at Ridgway in 1953.

Engine 461, often leased to the RGS in the 1940’s, became the second K-27 acquired by that railroad. This purchase in February of 1951 came at a time when the end was well in sight for the RGS. The 461 was slated for the scrapper’s torch when the RGS and D&RGW struck a purchase agreement that was favorable to the RGS’ limited resources. It briefly carried the so called “Rising Sun Herald” on its tender before joining the 455 for dismantling in 1953.

By the beginning of the 1950’s, the Denver and Rio Grande Western’s need for the surviving
K-27’s came full circle. With the ending of the RGS operations, and the coming abandonment of the narrow gauge line from Salida to Montrose, most of what remained of this faithful class of motive power chugged into our history books.