In 1903 the Denver & Rio Grande purchased fifteen narrow gauge "Mikado" type locomotives from the Baldwin Locomotive Company. These locomotives had outside frames and were delivered as Vauclain compound but were converted to simple engines between 1907 and 1909. They were designated as Class K-27 and the group was numbered 450 through 464. The simple two cylinder locomotives had 40" diameter drivers, 17" x 22" cylinders, a 200 psi boiler pressure and they exerted 27,022 pounds of tractive effort. The firebox was 113 square feet and the evaporative heating surface was 2149. The K-27s did not track well and derailed from time to time on the poorly maintained tracks. This earned them the nickname of "Mud Hens".
Twenty years after buying the "Mud Hens" the Rio Grande bought ten narrow gauge 2-8-2s from the American Locomotive Company. This group was designated as Class K-28 and was given road numbers 470 through 479. These locomotives had 44" diameter drivers, 18" x 22" cylinders, a 200 psi boiler pressure and they exerted 27,540 pounds of tractive effort. The firebox was 102 square feet, the evaporative heating surface was 1600 square feet and with the superheater the combined heating surface was 1,996 square feet. This group was well liked and the locomotives of the group were called "Sports Models". Seven, of this class were drafted into service during World War II and were put to work on the White Pass & Yukon Railroad in Alaska.
Just two years later, in 1925, ten more narrow gauge "Mikados" were added to the Rio Grande roster. This group came from Baldwin, designated as Class K-36 and assigned road numbers 480 though 489. These locomotives had 44" diameter drivers, 20" x 24" cylinders, a 195 psi boiler pressure and they exerted 36,164 pounds of tractive effort. The firebox was 145 square feet, the evaporative heating surface was 2,118 and with the superheater the combined heating surface was 2,693 square feet. This group of locomotives was never given a nickname.
Needing more motive power in the late 1920s the D&RGW's Burnham Shops in Denver began a program of building a new class of 2-8-2s. Ten were built by converting standard gauge 2-8-0s between 1928 and 1930. This group was designated as Class K-37 and was assigned road numbers 490 through 499. These locomotives had 44" diameter drivers, 20" x 24" cylinders, a 200 psi boiler pressure and they exerted 37,091 pounds of tractive effort. The firebox was 249 square feet, the evaporative heating surface was 2,102 square feet and with the superheater the combined heating surface was 2,597 square feet.
The D&RG had added a third rail to its tracks and ran both standard and narrow gauge motive power and rolling stock. Its Denver to Ogden main line was converted to standard gauge. The railroad needed standard gauge locomotives for its Denver to Pueblo freight service and it ordered fourteen for delivery in 1913 from Baldwin. These locomotives were designated as Class K-59 and were given road numbers 1200 through 1213. They had 63" diameter drivers, 27" x 30" cylinders, a 200 psi boiler pressure and they exerted 59,014 pounds of tractive effort. The firebox was 335 square feet, the evaporative heating surface was 3,700 square feet and with the superheater the combined heating surface was 4,495 square feet.
There was one more group of standard gauge "Mikados" used on the D&RGW. These locomotives were bought second hand from the Denver & Salt Lake in 1947. There were eight that were built by Lima in 1915, which were assigned road numbers 1220 through 1227, and two ALCO built locomotives that were built in 1916. The later pair received road numbers 1228 and 1229. These locomotives had 55" diameter drivers, 26" x 30" cylinders, a 200 psi boiler pressure and they exerted 62,700 pounds of tractive effort.
There are 22 surviving D&RGW 2-8-2s.
|Class||Qty.||Road Numbers||From Other RR||Year Acquired||Year Built||Builder||Notes|
Data from DeGolyer, Volume 25, p. 217. Works numbers were 21677, 21685 in February 1903; 21728-21729, 21781, 21788, 21796, 21803, 21824, 21832, 21845, 21854, 21894 in March; and 21910 and 21936 in April.This relatively large class of early narrow-gauge Mikados had the usual Vauclain compound cylinder layout of one LP and one HP in a casting on each side of the smokebox. Each side's cylinders received its steam (fresh for the HP, exhaust for the LP) through the same 10 1/2" (267 mm) balanced piston valves. Perhaps the compound cylinder arrangement driving such small wheels and traveling on 40-lb/yard (20 kg/metre) rail was the cause, but the "Mudhens" were not initially popular because of their tendency to derail. As they left the rail and skittered across the ties, according to bystanders, they had a waddling gate like that of a hen, hence the nickname. The spec for the class included the requirement to scale 4% grades, negotiate 24 degree curves on the main, 30 deg curves in sidings. As with most North American railroads that bought compound locomotives, the DR&G's class 125s didn't remain compounds for long as the extra maintenance cost outweighed the fuel and water savings. See Locobase 3753 for the simple-expansion conversions that began in 1907.
Data from D&RGW 1 - 1952 Folio L Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also Chris Lane, "Mountain Models (Division of PSC) K-27", Model Railroading, July 2005, pp. 18-21, archived on the web at , last accessed 24 May 2008. Works numbers were 21677, 21685 in February 1903; 21728-21729, 21781, 21788, 21796, 21803, 21824, 21832, 21845, 21854, 21894 in March; and 21910 and 21936 in April.Locobasee 16465 shows this class in 1903, when it arrived as Vauclain compounds (two 13" HP, two 22" LP cylinders. Within four years, the D&RG began converting the class to two-cylinder simple engines in 1907-1911. Curiously, during the conversion, the railroad elected to install slide valves operated by Stephenson link motion in place of the Walschaert-actuated piston valves that had fed the two cylinders on each side. While 10 were retrofitted with 11" (279 mm) piston valves when superheated in the 1920s (see Locobase 9465), 462, alone among the saturated survivors, eventually received piston valves as well. 459 later went on to serve the Nacional de Mexico as their 401.
Data from D&RGW 1 - 1952 Folio L Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.When the little Mikes shown in Locobase 3753 received superheaters, the boilers underwent the usual exchange of tubes in favor of flues -- 119 of the former were removed to make room for 22 of the latter. Even though the tractive effort rating remained unchanged, the steam distributed by relatively capacious 11" diameter piston valves was drier and consequently gave more push per pulse. The first few conversions (454, 456, 458, 461) retained the inside-frame valve chest location (so that from the front the cylinders "tilt" in toward the boiler from either side). The later conversions favored the outside-valve chest location that lined up the valve with the Walschaert valve gear. On an Internet forum, a post from El Coke (Ed Coker), titled Runnning [sic] the last K-27s and time-stamped December 12, 2005 07:39PM gave a thorough "review" of how at least one of the class felt to run: "This was a very enjoyable engine to run. The engine was comfortable to operate, with controls placed where an engineman did not neeed to reach far to operate. It had a very reponsive throttle and tracked very well, though not quite as good as 473 and 476. It had a short wheelbase and a big overhang in the back-like the 480s, and would nose around in curves but with none of the violence the 480s would display. It also, like the 470s, could go relatively fast and feel safe. It had no backhead insulation so the cab was hot. The lifting injectors always worked fine. The negative-and it was a big one-was the engine steamed poorly. It served the engineeer and fireman well to clean the fire themselves- and as thoroughly as possible, especially in front. Earl and I agreed that if the perfect notch in the cutoff and the perfect notch in the throttle were found it would run up Cumbres without running out of steam. " Another correspondent -- Re: Runnning the last K-27s, Posted by: earl (IP Logged), Date: December 15, 2005 08:40AM -- added his comments about why the K-27 steamed poorly: "The problem with K27's is the firebox is very shallow with little room up front between the grates and the arch. You had to be a good shot with the scoop. Too high and you'd hit the arch and the coal would fall in the middle. Too low and the coal would land short of the front. Either way, you end up with a pile about 2 feet from the front - a pile that would extend from the grates all the way to the arch - with nothing burning against the flue sheet. The shallow box didn't allow much room for air to combine with the gases, which effected its ability to steam and keep the smoke down." "Earl" continues with fascinating detail about what it took to fire a flawed design: "It took lots of little scoops of coal to keep 463 against the peg. Her hard draft would burn the coal right off the scoop. You had to keep after her, and be on your feet most of the time (right next that unlagged backhead). She had real big injectors (10's) which were oversized for her. They wouldn't cut back far enough to run all the time and you had to trade water and steam - fire the gun off when you had 199.95 lbs, then fire until you dropped to 192 or so, kill the gun, get your steam back, start the gun, etc. You were a real busy fireman. Even at its best by the time you got to below Coxo the fire was getting deep, and her steaming ability was beginning to fade (along with the fireman). If a stop at Cresco was made, it gave the fireman a chance to shake the fire down a bit, which amde life on the upper part of the hill much easier. After a few days on 463, firing 489 was like laying off." Retirements began in the late 1930s. 458-459 enjoyed an unusual post-DRG career beginning January 1942 when they were sold to the Nacional de Mexico as their class KR-7 #400-401, converted to standard-gauge running in 1949 (July and June, respectively) and renumbered 2250-2251 in classes KR-7 and KR-8. Considering that meant lengthening the axles by more than a foot and a half, this was a pretty drastic step to take on 40-year-old locomotives. The enlargement must have proved satisfactory, for the NdeM didn't retire 459/401/2251 until 1957 and only condemned 458/400/2250 in 1962.
Data from D&RGW 12 - 1937 Folio 10 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also Chris Lane, "Mountain Models (Division of PSC) K-28", Model Railroading, April 2006, pp. 17-20, archived on the web at , last accessed 24 May 2008 and an extended discussion at http://openbuildings.com/buildings/durango-and-silverton-narrow-gauge-railroad-profile-31988#, last accessed 28 October 2011; and Joe Rubino "Ole' Locomotive No. 476 ready to rumble back into service on Durango railroad this winter", Denver Post, 9 October 2017 (as updated), 12:15 PM , last accessed 24 December 2017 at https://www.denverpost.com/2017/10/08/ole-locomotive-no-476-back-in-service-durango-railroad-winter/. (Thanks to Chris Hohl for his 5 April 2015 email stating the tender's coal capacity.) Works numbers were 64981-64990 in September 1923.These were first Mikes procured by the Denver & Rio Grande Western's narrow-gauge line since the "Mudhens" of 1903 (see Locobase 3753, 9465). Drury (1993) notes that they were nicknamed the "Sports Models" (probably from the taller drivers allowing more speed) and adds that tractive effort was little different from the earlier class. Lane notes the distinguishing features of these Mikes, including a large counterweight just on the fhird driver (to balance the main rod big end) and a cross-compound air pump on the left-hand smokebox door. They replaced Ten-Wheelers pulling passenger trains on the Alamosa-Durango and Salida-Gunnison services. These runs included the last named-narrow gauge passenger train, the San Juan. Lane says the success of the design, which ran smoothly and powerfully, led to other orders including a set of four for the Oahu Land & Railway Company. When World War II began, seven of the ten in the class were appropriated by the US Army and sent to the Yukon & White Pass Railroad; 470-472, 474-475, 477, and 479 were renumbered in sequence 250--256. They didn't return to the D&RGW, but were scrapped in 1945 in Seattle (6) and 472 in Ogden, Utah . The other three ran in the Rockies for as long as the DRG&W maintained its narrow-gauge division, being retired only in the late 1950s. All three later went to the Durango & Silverton to operated on those rails, a service that soon transformed into a thriving tourixt-line attraction. 476 was taken out of service in 1999 when its boiler ticket expired. In his October 2017 Denver Post article, Joe Rubino wrote that the 476's overhaul was delayed by the commercial side effects of the 2002 Missionary Ridge wildfire that burned 71,739 acres near Durango and significantly depressed tourist ridership. Retooling the Durango & Silverton's "brand" to offer a wider variety of locomotive-hauled experiences proved successful and the D&S were at last able to begin the long-stalled overhaul, which ultimately required $1 million to complete. The first revenue run was scheduled for the Winter Photography Train on 17-18 February 2018.
Data from D&RGW 12 - 1937 Folio 10 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange see also http://openbuildings.com/buildings/durango-and-silverton-narrow-gauge-railroad-profile-31988#, last accessed 28 October 2011 and DeGolyer, Volume 76, pp. 283+. (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .) Works numbers were 58541, 58558-58559 in July 1925; 58584-58590 in August. (For some reason, the first engine was assigned road number 482. The others were numbered in order of their works numbers.)The last new narrow-gauge locomotives bought by the D&RGW. Drury (1993) notes that these had outside frames (drivers between the frames, counterweights and crankpins visible outside the frames). Piston valve diameter was 11" (279 mm). A general statement in Baldwin's specifications sheets indicate the close fit between design and anticipated operating environment: "Engines to operate at elevation of 11,000 ft [3,353 m]. Maximum emergency speed for stability, on 26 degree curves, 25 miles per hour [40 km/h]. Operating speed on 26 degree curves, 15 mph [24 km/h]. Track gauge on 26 degree curve, 36 1/2" [927 mm]. Track elevation on 26 degree curve, 3 3/4" [95 mm]." Another interesting spec is the one addressing steam flow, in which the designers state that "throttle, dry pipe and steam pipe area based on approximate steam flow of 6,000 ft per minute under maximum power, and not over 7,000 ft per minute through superheater." Locobase doesn't remember seeing this particular ratio described in any other Baldwin spec, although clearly such considerations preoccupied builders and operators during the whole of the steam age. , last accessed 24 May 2008 -- A website detailing the DRG&W's narrow-gauge operation -- notes: "They had one third more pulling power than the K-28s [Locobase 5042] and were used on the steepest grades." The author adds: "Most of the people who ran the narrow gauge engines consider the K36s to be the best narrow gauge engines on the D&RGW. " They were not without their flaws, however, the most frequently mentioned being poor riding qualities.
Data from D&RGW 1 - 1952 Folio L Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also George Woodman Hilton, American Narrow-Gauge Railroads (Stanford, Calif: Stanford University Press, 1990, p. 155; , last accessed 8 July 2014; and Michael P. Spera & Kathy McCardwell, preparers, "Denver & Rio Grade Western Locomotive No.491 (K-37 2-8-2 'Mikado')", Colorado State Register of Historic Properties Nomination Form, register listing approved 23 January 2014, archived at https://www.historycolorado.org/sites/default/files/media/documents/2018/5jf5177.pdf, last accessed 27 September 2019; N D Holmes "DRGW 493 Returns"-Rio Grande News, posted 24 January 2020 on DRGW.net. (Thanks to Chris Hohl for his 28 February 2020 email for reporting the 493's conversion to oil-firing, tender oil capacity, and its return to operational service in January 2020.)This class represents a rare instance in which a standard-gauge locomotive design was converted to narrow-gauge operation. Obviously trying to put as much power over a single set of wheels as was possible on three-foot gauge as cheaply as possible, chief mechanical engineer at the Denver Burnham shops PC Withrowe and George R Ballard of General Iron-Steams-Roger took its class of Baldwin-built C-41 Consolidations (see Locobase 1461), added a trailing axle under the firebox and squeezed the wheels 1 1/2 feet closer together in a new frame. The C-41s made over in this program were originally numbered 1008, 1014, 1020-1021, 1026, 1004, 1023, 1003, 1009, and 1025. The resulting Mikado was slightly smaller than the built-for-3-ft K-36 (see Locobase 13), but put down a 3,600-lb (1,633 kg) higher axle loading. Hilton comments that the K-37s "...were particularly identified with the Monarch branch, which combined difficult curves and heavy mineral traffic." And noting a structural feature, adds, "The engines were a demonstration of the attractions of the outside frame, allowing a large boiler of standard-gauge dimensions on 3' track." (Hilton also observes that so large a boiler on the narrow-gauge was a moderately scaled vessel on the 4' 8 1/2" alignment.) 493-494 and 497 were modified with steam heating equipment to serve the Shavano passenger trains between Salida and Gunnison. According to the CSRHP Nomination Form, 491 "operated along the entire D&RGW system, from the tortuous four percent grade of Marshall Pass, to the gun barrel of the Valley Line, up and over Cumbres Pass, and on to Farmington, New Mexico." The specifications reflect a later update in which a few boiler tubes were removed as part of a firebox overhaul that resulted in the installation of 46 sq ft (4.25 sq m) of thermic syphons to contribute to the firebox heating surface area. All but two were preserved after the narrow-gauge era ended; 496 was scrapped in 1955 and 490 was scrapped in 1963-1964 .497 operated on the Durango & Silverton until it was traded to the C&TS for K-36 #482. Its tube life expired in 2003, but is "stored serviceable." 491's restoration to service at the Colorado Railroad Museum (Golden, CO) ended with re-entry to operational service on 30 July 2014. 493 was restored to operating condition on 24 January 2020 as an oil-burning engine trailing a tender holding 2,250 US gallons (8,516 litres) of fuel. ND Holmes wrote that several ideas for restoring for the 493 were considered. "After the 416 Fire in 2018," Holmes added,"the D&S considered a new option for 493 - convert the engine to an experimental oil burner to lessen the fire danger posed by ejected cinders. The railroad borrowed SP narrow gauge #18 in 2018-2019 to experiment with oil burners and train crews.." Its first revenue run came on 14 February hauling the "Romance on the Rails" Cascade Canyon train. (See the details of the restoration, including the installation of nearly 600 flexible staybolts in the firebox, at "D&SNGRR Announces Locomotive No. 493's Return Following Extensive Multi-Year Rebuild, Conversion" at , last accessed 8 March 2020. In addition, several members were on display at several Colorado locations: 493 at the Freight House Museum, Silverton; 494-495 at the Cumbre &Toltec Scenic yard in Antonito; 498 at the Durango & Silverton in Durango, and the 499 at Royal Gorge Park at Canon City, CO.
Data from 1937 & 1952 D & RGW locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 45, pp. 322+. Works numbers were 38772-38781 and 38870-38873 in November 1912.As delivered, this class had relatively capacious 16" (406 mm) diameter piston valves. According to Drury (1993), these engines were spirited enough to pull passenger trains over the Moffatt Tunnel route in the 1930s-1940s. The operating environment included 4% grades, rail elevations up to 6" (152 mm), and 16 degree curves. Engine numbers reflect D&RGW renumbering in 1924. By 1937's diagram, the class's boiler pressure rating had climbed to 200 psi. Ten of the class used Sellers exhaust injectors; Elesco exhaust injectors appeared in 1200, 1206-1208. Duplex mechanical stokers supplied coal to fireboxes in 1200, 1202-1203, 1206-1207, and 1209-1213. Simplex stokers were fitted in 1201, 1204-1205. Tenders with one of four different water capacities trailed behind the class as follows: 1201, 1204, 1211 7,400 US gallons (28,009 litres) 1212 8,300 gallons (31,416 litres) 1200, 1203, 1205-1206 8,400 gallons (31,794 litres) 1202, 1213 8,600 gallons (32,551 litres). When fitted with 10" (254 mm) coal boards, all could carry 17 tons (15.4 tonnes) of coal. 1201 was totalled in 1938 when it collided with Denver & Salt Lake 201 (Locobase 1465). See Locobase 16280 for a later update of the firebox to include much more heating surface area.
Data from 1937 & 1952 D & RGW locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.As delivered (see Locobase 1464), this class had relatively capacious 16" (406 mm) diameter piston valves. In their final form, these engines had 12" (305 mm) valves and the fireboxes used Rosebud grates. The firebox heating surface included 38 sq ft (3.53 sq m) of arch tubes to which had been added 60 sq ft (5.57 sq m) of syphons. 1202 was fitted with circulators instead, which added 45 sq ft (4.18 sq m) to the original firebox area, which added up to 320 sq ft (29.73 sq m). 1202's boiler tubes and flues also measured 6" (152 mm) longer. It also trailed a longer tender that carried 13,000 US gallons (49,205 litres) of water and 17 tons of coal (20 tons with 10"/254 mm coal boards). Loaded weight with the larger coal capacity came to 231,400 lb (104,961 kg), which pushed the engine and tender power system's weight to 507,400 lb (230,153 kg). According to Drury (1993), these engines were spirited enough to pull passenger trains over the Moffatt Tunnel route in the 1930s-1940s. 1206 was the first to be scrapped, going in March 1948, 1211 and 1203 followed in the same year (June and December, respectively). 1210 went to the ferro-knacker's in July 1949, 1212 and 1204 in June and July 1950. 1208's day came in August 1952, class leader 1200's in July 1954, 1205 and 1213 in February 1955, 1202 and 1209 in June, and 1207 in September 1956.
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Railroad||Denver & Rio Grande (D&RGW)||Denver & Rio Grande (D&RGW)||Denver & Rio Grande Western (D&RGW)||Denver & Rio Grande Western (D&RGW)||Denver & Rio Grande Western (D&RGW)|
|Number in Class||15||15||10||10||10|
|Road Numbers||450-464||450-464||452-456, 458-459, 461, 463-464||470-479||480-489|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||11.42 / 3.48||11.42 / 3.48||11.42 / 3.48||12.25 / 3.73||12.25 / 3.73|
|Engine Wheelbase (ft / m)||24.50 / 7.47||24.50 / 7.47||24.50 / 7.47||28.83 / 8.79||28.08 / 8.56|
|Ratio of driving wheelbase to overall engine wheelbase||0.47||0.47||0.47||0.42||0.44|
|Overall Wheelbase (engine & tender) (ft / m)||51.04 / 15.56||51.04 / 15.56||53.50 / 16.31||58.65 / 17.88|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||27,475 / 12,462||27,969 / 12,687||28,448 / 12,904||36,064 / 16,358|
|Weight on Drivers (lbs / kg)||100,000 / 45,359||104,255 / 47,289||108,300 / 49,124||113,500 / 51,483||143,850 / 65,249|
|Engine Weight (lbs / kg)||125,500 / 56,926||136,850 / 62,074||140,250 / 63,616||156,000 / 84,867||187,100 / 84,867|
|Tender Loaded Weight (lbs / kg)||72,000 / 32,659||83,300 / 37,784||83,300 / 37,784||98,500 / 44,679||99,500 / 45,132|
|Total Engine and Tender Weight (lbs / kg)||197,500 / 89,585||220,150 / 99,858||223,550 / 101,400||254,500 / 129,546||286,600 / 129,999|
|Tender Water Capacity (gals / ML)||3500 / 13.26||4100 / 15.53||4100 / 15.53||5000 / 18.94||5000 / 18.94|
|Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)||8.50 / 8||8.50 / 8||8||9.50 / 9|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||42 / 21||43 / 21.50||45 / 22.50||47 / 23.50||60 / 30|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||40 / 1016||40 / 1016||40 / 1016||44 / 1118||44 / 1118|
|Boiler Pressure (psi / kPa)||200 / 13.80||200 / 13.80||200 / 13.80||200 / 13.80||195 / 13.40|
|High Pressure Cylinders (dia x stroke) (in / mm)||13" x 22" / 330x559||17" x 22" / 432x559||17" x 22" / 432x559||18" x 22" / 457x559||20" x 24" / 508x610|
|Low Pressure Cylinders (dia x stroke) (in / mm)||22" x 22" / 559x559|
|Tractive Effort (lbs / kg)||23,424 / 10624.96||27,022 / 12256.99||27,022 / 12256.99||27,540 / 12491.95||36,164 / 16403.73|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.27||3.86||4.01||4.12||3.98|
|Tubes (number - dia) (in / mm)||216 - 2.25" / 57||216 - 2.25" / 57||97 - 2.25" / 57||106 - 2.25" / 57||137 - 2.25" / 57|
|Flues (number - dia) (in / mm)||22 - 5.375" / 137||22 - 5.5" / 140||30 - 5.5" / 140|
|Flue/Tube length (ft / m)||16 / 4.88||16 / 4.88||16 / 4.88||16 / 4.88||16 / 4.88|
|Firebox Area (sq ft / m2)||106 / 9.85||106 / 9.85||113 / 10.50||102 / 9.48||145 / 13.47|
|Grate Area (sq ft / m2)||30.20 / 2.81||30.20 / 2.81||30.17 / 2.80||30.10 / 2.80||40.20 / 3.74|
|Evaporative Heating Surface (sq ft / m2)||2133 / 198.16||2133 / 198.16||1526 / 141.82||1594 / 148.70||2118 / 196.84|
|Superheating Surface (sq ft / m2)||407 / 37.83||422 / 36.80||575 / 53.44|
|Combined Heating Surface (sq ft / m2)||2133 / 198.16||2133 / 198.16||1933 / 179.65||2016 / 185.50||2693 / 250.28|
|Evaporative Heating Surface/Cylinder Volume||630.94||369.03||264.01||245.99||242.61|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||6040||6040||6034||6020||7839|
|Same as above plus superheater percentage||6040||6040||7301||7284||9485|
|Same as above but substitute firebox area for grate area||21,200||21,200||27,346||24,684||34,213|
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Railroad||Denver & Rio Grande Western (D&RGW)||Denver & Rio Grande (D&RGW)||Denver & Rio Grande (D&RGW)|
|Number in Class||10||14||13|
|Road Numbers||490-499||1200-1213||1200, 1202-1213|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||12.25 / 3.73||16.50 / 5.03||16.50 / 5.03|
|Engine Wheelbase (ft / m)||29.08 / 8.86||34.75 / 10.59||34.75 / 10.59|
|Ratio of driving wheelbase to overall engine wheelbase||0.42||0.47||0.47|
|Overall Wheelbase (engine & tender) (ft / m)||56.15 / 17.11||66.62 / 20.31||66.62 / 20.31|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||39,700 / 18,008||54,000 / 24,494|
|Weight on Drivers (lbs / kg)||148,280 / 67,259||213,000 / 96,615||212,000 / 96,162|
|Engine Weight (lbs / kg)||187,250 / 84,935||283,000 / 128,367||276,000 / 125,192|
|Tender Loaded Weight (lbs / kg)||120,000 / 54,431||160,000 / 72,575||162,700 / 73,800|
|Total Engine and Tender Weight (lbs / kg)||307,250 / 139,366||443,000 / 200,942||438,700 / 198,992|
|Tender Water Capacity (gals / ML)||6000 / 22.73||8000 / 30.30||8600 / 32.58|
|Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)||9 / 8||14 / 13||14 / 13|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||62 / 31||89 / 44.50||88 / 44|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||44 / 1118||63 / 1600||63 / 1600|
|Boiler Pressure (psi / kPa)||200 / 13.80||170 / 11.70||200 / 13.80|
|High Pressure Cylinders (dia x stroke) (in / mm)||20" x 24" / 508x610||27" x 30" / 686x762||27" x 30" / 686x762|
|Tractive Effort (lbs / kg)||37,091 / 16824.21||50,162 / 22753.13||59,014 / 26768.33|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.00||4.25||3.59|
|Tubes (number - dia) (in / mm)||173 - 2" / 51||203 - 2.25" / 57||203 - 2.25" / 57|
|Flues (number - dia) (in / mm)||30 - 5.375" / 137||36 - 5.5" / 140||36 - 5.5" / 140|
|Flue/Tube length (ft / m)||14.17 / 4.32||20 / 6.10||20 / 6.10|
|Firebox Area (sq ft / m2)||249 / 23.13||234 / 21.74||335 / 31.12|
|Grate Area (sq ft / m2)||46.60 / 4.33||63 / 5.85||63 / 5.85|
|Evaporative Heating Surface (sq ft / m2)||2102 / 195.28||3648 / 338.91||3710 / 344.67|
|Superheating Surface (sq ft / m2)||495 / 45.99||844 / 78.41||795 / 73.86|
|Combined Heating Surface (sq ft / m2)||2597 / 241.27||4492 / 417.32||4505 / 418.53|
|Evaporative Heating Surface/Cylinder Volume||240.78||183.50||186.62|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||9320||10,710||12,600|
|Same as above plus superheater percentage||11,091||12,745||14,868|
|Same as above but substitute firebox area for grate area||59,262||47,338||79,060|