The Denver & Rio Grande Western K-37 is a series of class of 2-8-2 "Mikado" type coal-fired narrow gauge steam locomotives built by the Baldwin Locomotive Works as 2-8-0s in 1902 for the Denver & Rio Grande Western Railroad (D&RGW) and modified to be 3 foot gauge 2-8-2s in 1924.
Originally known as the standard gauge class 190 2-8-0 "Consolidation" types, and later re-designated as class C-41 (meaning 41,000 lbs tractive effort) in 1924, their boilers were used on the K-37 and the tenders were reguaged to 3 foot narrow gauge between 1928 and 1930 at the D&RGW's Burnham Shops in Denver with a host of new parts, including new outside frames and smaller 44' drivers.
Although the K-37s were actually about 2% lighter compared with the later K-36s, they were perceived to be much harder on D&RGW tracks; particularly on the Animas Canyon section of the route as far as Canon City.
In regular service, the K-37s were commonly found on the Crested Butte Branch between Salida and Gunnison, CO, as well as over the Cumbres Pass from Alamosa to Chama, NM. Like the K-36s, they were not permitted West of Gunnison or on the Silverton branch; though at least three of the class, Nos. 491, 493, and 499, were equipped with steam heating for passenger train service on the San Juan Express and the Shavano.
As of today, locomotive 491 is operational at the Colorado Railroad Museum in Golden, CO. Locomotive 493 is operational at the Durango & Silverton Narrow Gauge Railroad (D&SNG) in Durango, CO and has been converted to burn oil instead of coal. Locomotive 497 was originally restored by the D&SNG in 1984 and previously operated at the Cumbres & Toltec Scenic Railroad (C&TS) between Chama, NM and Antonito, CO until being taken out of service indefinitely in October 2002. It currently resides in Chama awaiting a future overhaul. On February 16, 2022, the C&TS announced that locomotives 492 and 497 will both be evaluated to see which one is the best candidate for restoration back to operating condition. After careful evaluation, 492 was chosen for the restoration instead of 497. Locomotives 494 and 495 are both on static display in Antonito, CO. Locomotive 498 is stored partially dismantled in Durango, CO. Lastly, locomotive 499 is on static display at the Royal Gorge Bridge & Park in Canon City, CO.
Roster[]
| Image | Number | Builder | Build Date | Serial No. | Operator | Status | Notes |
|---|---|---|---|---|---|---|---|
 |
490 | D&RGW Burnham Shops | 1928 | 20695 | Denver & Rio Grande Western | Scrapped Sometime Between 1963 and 1964 | Retired from the D&RGW in 1962. |
 |
491 | D&RGW Burnham Shops | 1928 | 20829 | Colorado Railroad Museum | Operational | Retired from the D&RGW in 1963. Acquired by History Colorado in 1979. Moved to the Colorado Railroad Museum in 1985; ownership of the locomotive was transferred to the museum in 2013. Restored to operation and made its first public run on August 30, 2014. |
 |
492 | D&RGW Burnham Shops | 1928 | 20749 | Cumbres & Toltec Scenic Railroad | Stored Out of Service | Went to the C&TS in 1970. Currently being restored to operating condition as of August 9, 2023, as it was chosen instead of 497. |
| 493 | D&RGW Burnham Shops | 1928 | 20550 | Durango & Silverton Narrow Gauge Railroad | Operational | Retired from the D&RGW in 1968. Went to the D&SNG in March 1981. Restored to operating condition and converted to burn oil on January 24, 2020. | |
 |
494 | D&RGW Burnham Shops | 1928 | 20748 | Cumbres & Toltec Scenic Railroad | Stored Out of Service | Retired from the D&RGW in 1962. Went to the C&TS in 1970. Currently on display in Antonito, Colorado. |
 |
495 | D&RGW Burnham Shops | 1928 | 20522 | Cumbres & Toltec Scenic Railroad | Stored Out of Service | Retired from the D&RGW in 1962. Went to the C&TS in 1970. Currently on display in Antonito, Colorado. |
 |
496 | D&RGW Burnham Shops | 1930 | 20751 | Denver & Rio Grande Western | Scrapped in 1955 | |
 |
497 | D&RGW Burnham Shops | 1930 | 20521 | Cumbres & Toltec Scenic Railroad | Stored Out of Service | Went to the D&SNG in March 1981. Restored to operating condition in 1984. Traded to C&TS in October 1991 in exchange for K-36 No. 482. Taken out of service indefinitely in October 2002. Currently stored in Chama, New Mexico; awaiting a possible future overhaul. After careful evaluation of both 497 and 492, the latter was chosen for restoration. |
 |
498 | D&RGW Burnham Shops | 1930 | 20640 | Durango & Silverton Narrow Gauge Railroad | Stored Out of Service | Went to the D&SNG in March 1981. |
 |
499 | D&RGW Burnham Shops | 1930 | 20753 | Royal Gorge Park | Stored Out of Service | Retired from the D&RGW in 1970. Went to the D&SNG in March 1981. Traded to Royal Gorge Park in May 1999 for display in exchange for K-36 No. 486. |
