D&RGW K-37 Mikado #497 in Chama on the Cumbres & Toltec Scenic Railroad.
At the end of the twenties, the relative prosperity of the railroad and its booming traffic prompted the Denver & Rio Grande Western to modernize again its narrow gauge motive power with new, more powerful engines. The Rio Grande considered the offers from several locomotive builders for articulated designs but eventually, in light of the class K-36 locomotives succes, chose to get ten more Mikado, obtained this time by converting old standard gauge engines to narrow gauge. This new class, designated K-37 and numbered from 490 to 499, was formed of rebuilt Rio Grande standard gauge Consolidation class C-41, originally manufactured by Baldwin Locomotive Works in 1902. Ten of these Consolidation were rebuilt into narrow gauge outside frame Mikado by the D&RGW at its Burnham shops in Denver, keeping the C-41 original boiler and cab, and using new cylinders, a new frame and narrow gauge wheel set, again provided by Baldwin. Numbers 490 to 495 were delivered in 1928 and numbers 496 to 499 in 1930. The original tenders of the C-41 were reused on the K-37, including their trucks, with only the axles regauged to narrow gauge. The K-37 were the heaviest and most powerful Rio Grande narrow gauge locomotives, however they were not considered as good as the K-36 by the railroad, because of the older design of their boiler and the rigidity of their frame causing sometimes derailments.
K-37 #497 in the snow at Cumbres Pass.
Like the K-36, the K-37 were mainly freight engines, but they were also used on passenger trains, and in 1936-37 numbers 493, 494 and 499 were modified to provide steam heating and pull the new Shavano between Salida and Gunnison. The K-37 initially operated out of Salida on Marshall Pass and on the Monarch branch, and then throughout the Rio Grande narrow gauge system, except on a few branch lines where weight restrictions were in place. Some K-37 such as #494 were equipped with 3-way couplers on their tender, allowing them to pull standard gauge freight cars on the dual gauge lines of the Rio Grande system, particularly between Alamosa and Antonito, without the need of an idler car. Engine #496 suffered a serious boiler failure and was scrapped in 1955, but the other K-37 remained active, some ot them until the end of the sixties, only gradually sidelined by the Rio Grande as the traffic on the narrow gauge dwindled or because of mechanical breakdowns. Only #490 was stored inactive in 1962 and scrapped a few years later, but the eight remaining K-37 survived to date. The Rio Grande donated #491 to the Colorado Historical Society in 1970, and it has been on display at the Colorado Railroad Museum in Golden since 1985. In 1970 as well, number 492, 494 and 495 were bought by the States of Colorado and New Mexico, and transferred to the Cumbres & Toltec Scenic Railroad. All three of them remained out of service since then, #492 is stored in Chama, and #494 as well as 495 are on display in Antonito. As for number 493, 497, 498 and 499, they were sold to the Durango & Silverton Narrow Gauge Railroad in 1981. #493 is on display in Silverton and #498 is stored in Durango, both out of service. #497 had been overhauled by the D&RGW in 1967, then stored serviceable in Durango the following year. It was returned to service by the Durango & Silverton Narrow Gauge Railroad in 1984, and operated on this tourist railroad for the next 7 years. But because of its wheelbase slightly longer than the one of the K-36 and its heavier weight, #497 was considered too harsh on the track and in 1991 the Durango & Silverton Narrow Gauge Railroad traded it in for Cumbres & Toltec Scenic Railroad K-36 #482. The later pressed #497 into service the year after, and it has been operating regularly on this tourist railroad without problems since then, as the curves between Chama and Antonito are not as sharp as between Durango and Silverton. Finally, #499 is now on display at the Royal Gorge Park near Canon City, after an exchange with K-36 #486 in 2001.
Eight of the ten K-37 built have been preserved today. #491 is at the Colorado Railroad Museum, number 493 and 498 on the Durango & Silverton Narrow Gauge Railroad, number 492, 494, 495 and 497 at the Cumbres & Toltec Scenic Railroad, and #499 on display at the Royal Gorge Park. Among the survivors, only #497 is operational and in service on the Cumbres & Toltec Scenic Railroad.
K-37 #491 preserved at the Colorado Railroad Museum in Golden.
Non-operational #492 stored in the yard in Chama.
#493 in Silverton by the depot.
Rio Grande #494 on display in Antonito.
#497 in operation on the Cumbres & Toltec Scenic Railroad in Cumbres Pass.