Except for a couple of experimental diesel engines and a switcher, the Rio Grande narrow gauge roster exclusively consisted of steam locomotives. These steam engines remained active until the end of commercial operations on the D&RGW narrow gauge system in 1968 (after that, only the Durango - Silverton line remained active, essentially for tourist purposes and still using steam power). The first steam locomotive ordered by the Denver & Rio Grande in 1871 was a diminutive 2-4-0 (the Montezuma), a light and not very powerful engine. Follow-up orders were rapidly placed for heavier and more powerful engines, mostly Consolidation types, then at the beginning of the twentieth century the Rio Grande ordered its first Mikado. After the second World War, most of the locomotives on the Rio Grande narrow gauge roster were Mikado, supplemented with a few Consolidation engines from older classes.
The Rio Grande narrow gauge Mikado were of four different classes, all outside frame. After 1924, locomotive classes were identified by a letter corresponding to their wheel arrangement (K was used for Mikado), followed by a number representing the maximum tractive effort of the engine in thousand pounds. For instance, a K-36 was a Mikado with a maximum tractive effort of 36,200 pounds. Most of these Mikado have been preserved and some of them are operational on the Durango & Silverton and Cumbres & Toltec tourist railroads.
The K-37 class of Mikado was obtained in the late twenties by reusing boilers from old standard gauge Consolidation, put on new narrow gauge wheel sets and frames.
Evolution of the Rio Grande narrow gauge motive power
D&RGW C-19 Consolidation #346 under steam at the Colorado Railroad Museum in Golden.
In its early days, between 1871 and 1873, the Denver & Rio Grande only had 12 narrow gauge steam locomotives, four 2-4-0 for passenger service weighting only 25,000 lbs and eight 2-6-0 Mogul a bit heavier (35,000 lbs) for freight service, all purchased new from Baldwin Locomotive Works. In 1873, a 0-4-4-0 double-ended Fairlie was added to the roster, this particularly original locomotive was a twin boiler engine built by the Vulcan Foundry Company in England and derived from locomotives of the same design operating on the Festiniog Railway, a two-foot gauge railroad in Wales, which was used by Denver & Rio Grande founder General Palmer as a model for his own railroad. It has been in use intermitently for about ten years, but eventually was not found to be satisfactory and remained a one of a kind, and the only Fairlie ever to see operation the USA. Then between 1876 and 1879, the railroad purchased additional Mogul locomotives, heavier than the previous ones at 40,000 lbs each, and several 4-4-0 American for passenger service, still all from Baldwin. But in 1876, the Rio Grande truely became a mountain railroad when it started to build over La Veta Pass, and the 4% grade of the new line required the use of more powerful locomotives. In 1877, Baldwin provided the Rio Grande with its first 2-8-0 Consolidation, its four drivers allowed to increase the pulling power of the locomotive while keeping an axle-load low enough to run on the light track used by the railroad at the time. From 1877 to 1881, the Denver & Rio Grande expanded tremendously by building new lines, and accordingly the railroad purchased over 150 Consolidation, a type that would become its standard freight engine for a quarter of a century. These Consolidation, built par Baldwin and Grant Locomotive Works, formed two series of engines : the class 56, and the class 60 (later designated class C-16) a little heavier than the former.
In the early 1880s, the Rio Grande purchased more American, then some 4-6-0 Ten-wheeler (including the future T-12), which would gradually replace the former on passenger trains. During the 1880s, the railroad also acquired two new series of Consolidation, the class 71 (future class C-17) and the class 70 (future class C-19), the later, more powerful, were restricted to the Marshall Pass line in their early career because of their weight. Then, beginning in 1887, the Rio Grande started to standard gauge its mainline between Denver and Ogden, Utah. Consequently and also because of the decline of the mining industry in the Rockies, a lot of narrow gauge locomotives became surplus after 1888 and a number were sold to other narrow gauge railroads, particularly the Rio Grande Southern. The Denver & Rio Grande did not order any more narrow gauge locomotives until the end of the nineteenth century and the railroad only took delivery of a new series of narrow gauge engines in 1903, for the first time a type 2-8-2 Mikado (the class 125, later designated class K-27). The 2-8-2 wheel arrangement and their outside frame allowed the Mikado to have a larger boiler because its weight could be supported by the rear truck of the locomotive. These engines were more powerful than a Consolidation with its boiler restricted in size because it had to be located on the drivers between the frame, thus the Mikado had about twice the hauling power of a class 70 Consolidation.
With the arrival of modern Mikado on the railroad and more lines been standard gauged, the Rio Grande could scrap the oldest of its Consolidation (mainly from class 56) and only the most powerful Consolidation remained active. Between 1916 and 1920, the railroad acquired several relatively modern second hand Consolidation from two recently abandonned Colorado narrow gauge railroads, six came from the Florence & Cripple Creek Railroad (and would form the class C-18), and three outside frame engines from the Crystal River Railroad (two would become class C-21 engines, the third the unique member of class C-25). Then in 1923 the Rio Grande purchased a second series of Mikado to be used more specifically in passenger service, the class 140, which would become the class K-28 a year after. In 1924, the recently reorganized Denver & Rio Grande Western partly renumbered its steam engines and changed its motive power classification scheme. The locomotive classes previously identified by a number correponding to the weight of the engine in thousand pounds, were from then on designated by a letter related to their wheel arrangement (T for Ten-wheeler, C for Consolidation, K for Mikado, etc), followed by a number representing the maximum tractive effort of the engine in thousand pounds. The D&RGW purchased another series of Mikado in 1925, the class K-36, which would be the last narrow gauge steam locomotives acquired new by the railroad. And finally in 1928 and 1930, the Rio Grande received its last Mikado, the class K-37, obtained by converting old standard gauge Consolidation. During the final years of operation, the four classes of Mikado were in charge of most of the traffic, except on a few branch lines (to Crested Butte, Baldwin and in the Black Canyon west of Gunnison as well as on the Montrose - Ouray line) where light track and bridges prevented the use of heavy engines. On these branch lines, all trains were hauled by the few Consolidation still on the roster.
In addition to the 22 narrow gauge Mikado still in existence (2 K-27, 3 K-28, 9 K-36 and 8 K-37), several other older types of Rio Grande locomotives have been preserved today. Two Ten-wheeler class T-12 survived, #168 is on display in Colorado Springs (photo on www.steamlocomotive.com) and #169 in Alamosa (photo on www.steamlocomotive.info). Several Consolidation have also been preserved, including three C-16. Number 223 is currently being restored at the Utah State Railroad Museum in Ogden, #268 is at the Pioneer Museum in Gunnison, and #278 is on display on a bridge at the entrance of the Black Canyon near Cimarron (photo on Dave Dye's website). The C-17 #420, sold to the Rio Grande Southern (RGS) in 1916 where it became #42, is now on display under this identity in the Durango roundhouse at the Durango & Silverton Narrow Gauge Railroad. Two C-18 have also been preserved today, #315 which has been on display at a public park in Durango for a long time, was recently restored by the Durango Railroad Historical Society in 2007 and is now operational (since then, it has run on the Durango & Silverton Narrow Gauge Railroad and the Cumbres & Toltec Scenic Railroad), and #318 is part of the Colorado Railroad Museum collection in Golden. Lastly, three C-19 have been preserved, #340 and RGS #41 (ex D&RG #409) were sold to Knott's Berry Farm in 1952 and are today both in service at this amusement park in California (photos on The Narrow Gauge Circle website) and a third, #346, is also operational at the Colorado Railroad Museum.