Kansas City, Mexico, & Orient / Santa Fe 2-10-0 "Decapod" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 801/2565 (Locobase 466)

Data for this version originally taken from Santa Fe drawings (aka Kansas City, Mexico, & Orient 801-805) preserved at [external link], last accessed 13 January 2010; that site ceased to exist. Data in the specification shown above from Santa Fe diagram on 186 at Kansas Memories Digital Archives at http://www.kansasmemory.org/item/221763/page/209, dated 15 January 1929, last accessed 8 December 2014 and DeGolyer, Volume 76, pp. 112+. See also E D Worley, Iron Horses of the Santa Fe (Dallas: Southwest Railroad Historical Society, 1976), p. 199. Works numbers were 58571-58575 in July 1925.

Five engines of Baldwin's standard catalog light 2-10-0 developed in the 1920s to put engines with this tractive effort on relatively light rails. E D Worley entered a delightful turn of phrase when he characterized this design as derived from the earlier Decapods meant for Russia, but "a different cup from the same samovar."

Piston valve diameter measured a relatively expansive 14" (356 mm). Superheater area was estimated at 721 sq ft (67 sq m), but was shown as 693 sq ft in 1929. Locobase notes that Baldwin measured the flue length as 17 ft 6 in, an outside length, while the Santa Fe calculated the length between tube sheets an inch shorter.

There was no mention of thermic syphons in the 1925 specs and the firebox's surface area was given as 203 sq ft (18.85 sq m). By the time the Santa Fe prepared a diagram dated 15 January 1929, however, firebox heating surface included 59.5 sq ft (5.5 sq m) in two syphons.

The KCM & O was absorbed by the Santa Fe in 1929.

Retired in 1953-55.


Class 987 (Locobase 5364)

Data from "Decapod Tandem Compound Freight Locomotive", American Engineer and Railroad Journal, Volume 76, No. 6 (June 1902), pp 191-194. See also DeGolyer, Volume 24, pp. 258+; and ATSF 7 - 1901 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange collection. (Thanks to Chris Hohl for his 22 March 2018 email supplying the link to the 1902 AERJ article and for noting the original spec for the boiler pressure and the engine's valve gear.) Works number was 20326 in April 1902.

At the time of its introduction several months after Alco's two decapods (Locobase 465), this four-cylinder tandem compound was the largest locomotive in the world. (The Santa Fe would break its own record within a year.).

It differed from Alco's design in several respects. Although the specification called for a similar 225 psi setting in the boiler, the Santa Fe had dropped this Baldwin's setting to 210 psi by 1903. Shorter strokes but larger cylinder diameters combined to supply slightly more overall cylinder volume. Fifty more tubes of similar diameter and more firebox heating surface area yielded 708 more sq ft (66.78 sq m) of evaporative heating surface, but a slightly smaller grate generated a higher than usual heating surface/grate area ratio. On the other hand, tandem compounds, like Baldwin or Alco's other four-cylinder designs, always had high compounding ratios than usually recommended (and achieved) in European compound designs.

One 13" (330 mm) piston valve served both ends of the long cylinder on each side of the smokebox. Some of the ratios strayed from the preferred band, most notably the relatively small amount of firebox heating surface area.

Tender water capacity later increased to 8,500 US gallons (32,173 litres) and 14 tons (12.7 metric tonnes) of coal.

987 saw service for less than a decade as a compound; she was simpled in 1911. The design was then superheated in 1917; see Locobase 8259 for the final result.


Class 987 - superheated (Locobase 8259)

Data from AT&SF 9 -1920 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Information about how many, when, and by whom this class was supplied from http://atsf.railfan.net/atsfstea.html (accessed 6 Feb 2006), the Santa Fe All-Time Steam Roster maintained by Evan Werkema.

Locobase 5364 shows this decapod as originally delivered in a Vauclain tandem-compound arrangement. In August 1911, the railroad deleted the HP cylinders and bushed the LP cylinders to created a two-cylinder, simple-expansion layout. A few years later they added a superheater and shortened tubes and flues by several inches. A notation in later diagrams shows the 987's tender carrying 2,515 US gallons (9,519 litres) of oil as an alternative.

In this configuration, the 987 persisted in its pusher work until cut up for scrap in August 1933.


Class 988 (Locobase 465)

Data from "Tandem Compound Decapod for the Santa Fe", Railway Age, Volume 33, No. 5 (31 January 1902), pp. 145-147. See also E D Worley, Iron Horses of the Santa Fe (Dallas: Southwest Railroad Historical Society, 1976); ATSF 7 - 1901 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange collectio; and [external link] (visited 23 July 2004), collection of newspaper clippings gathered by Ellington -- author of Steam Locomotives of the Santa Fe, A Former Shopman's Scrapbook --. Works numbers were 25340-25341 in December 1901.

Four-cylinder tandem compounds, with each long cylinder's pair of LP and HP chambers being supplied by the same long piston valve. These two Alcos preceded the single example from Baldwin (Locobase 5364) and briefly claimed the title of heaviest engines with the most heating surface area of any yet built.

Simpled in 1911, superheated in 1917 (Locobase 8264), retired in 1938.

Ellington quotes from the "TOPEKA STATE JOURNAL 2/24/1902:

New decapod work. One of the Santa Fe's new decapod engines, which are the heaviest engines in the world, made a record haul yesterday, says a Chicago paper. The engine pulled 703 tons up a grade 6 1/2 miles long, 158' to the mile. The track upon which the performance was made is known as the Cajon Pass, just west of the Sierra Nevada mountains. The load is the largest ever hauled by an engine up a 3% grade, but Vice President Kendrick expects to break this record. The management of the company is so pleased with the work of the decapod, that orders have been given for 75 of them at a cost of over $1,500,000 to be delivered by the latter part of August. Report of a test being made with the engines show that the wear upon the track is not so great as it is by many other, lighter engines. This is accounted for by the fact that the decapods have a rigid wheelbase of 20' and five sets of drivers, but while there are 232,000 lbs on the drivers, total, there are only 46,000 lbs. upon each set. This is less than that resting on the drivers of many passenger engines."

Ellington note: Only three of these decapods were ultimately acquired, derailing difficulties when backing, (among other operating problems), signalled the cancellation of the order for 75 additional copies from Baldwin, and served to introduce the following 2-10-2 type wheel arrangement; addition of a final pair of 'trailing' wheels largely solved the backing difficulties."


Class 988 - superheated (Locobase 8264)

Data from AT&SF 9 -1920 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Information about how many, when, and by whom this class was supplied from http://atsf.railfan.net/atsfstea.html (accessed 6 Feb 2006), the Santa Fe All-Time Steam Roster maintained by Evan Werkema.

Locobase 465 describes the delivery of these four-cylinder tandem compounds and notes that procurement of the remainder of a large order was cut off because these decapods derailed easily when backing up.

Even though they were now orphans together with 987 (Locobase 463), the Santa Fe went ahead with simpling and superheating. 989 was simpled in 1911, 988 in 1915. Note that although the railroad dropped the 988-class's boiler pressure considerably when they superheated the boiler (a frequent tradeoff for such conversions), they managed to retain almost all of the combined heating surface area.

In their altered states, this pair carried on until 1938 -- probably going forward most of the time.

Principal Dimensions by Steve Llanso of Sweat House Media
Class801/2565987987 - superheated988988 - superheated
Locobase ID466 5364 8259 465 8264
RailroadKansas City, Mexico, & Orient (ATSF)Santa Fe (ATSF)Santa Fe (ATSF)Santa Fe (ATSF)Santa Fe (ATSF)
CountryUSAUSAUSAUSAUSA
Whyte2-10-02-10-02-10-02-10-02-10-0
Number in Class51122
Road Numbers801-805/2565-2569940 / 987987988-989988-989
GaugeStdStdStdStdStd
Number Built512
BuilderBaldwinBurnham, Williams & CoSanta FeAlco-SchenectadySanta Fe
Year19251902191719011917
Valve GearWalschaertStephensonWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)20 / 6.1020.33 / 6.2020.33 / 6.2020 / 6.1020 / 6.10
Engine Wheelbase (ft / m)28.90 / 8.8129.83 / 9.0929.83 / 9.0928.92 / 8.8128.92 / 8.81
Ratio of driving wheelbase to overall engine wheebase 0.69 0.68 0.68 0.69 0.69
Overall Wheelbase (engine & tender) (ft / m)65.14 / 19.8559.50 / 18.1459.50 / 18.1462 / 18.9062.10 / 18.93
Axle Loading (Maximum Weight per Axle) (lbs / kg)46,600 / 20,86550,000 / 22,680
Weight on Drivers (lbs / kg)227,060 / 102,993237,800 / 107,864237,000 / 107,502232,000 / 105,234238,400 / 108,137
Engine Weight (lbs / kg)253,730 / 115,090267,800 / 121,472266,500 / 120,883259,800 / 117,843260,000 / 117,934
Tender Loaded Weight (lbs / kg)165,690 / 75,156134,700 / 61,099132,000 / 59,874135,000 / 61,235130,000 / 58,967
Total Engine and Tender Weight (lbs / kg)419,420 / 190,246402,500 / 182,571398,500 / 180,757394,800 / 179,078390,000 / 176,901
Tender Water Capacity (gals / ML)8500 / 32.207000 / 26.527000 / 26.527000 / 26.527000 / 26.52
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)3500 / 13.3011 / 1011 / 1011 / 10
Minimum weight of rail (calculated) (lb/yd / kg/m)76 / 3879 / 39.5079 / 39.5077 / 38.5079 / 39.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 144857 / 144857 / 144857 / 144857 / 1448
Boiler Pressure (psi / kPa)215 / 14.80210 / 15.50190 / 13.10225 / 15.50180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)25" x 30" / 635x76219" x 32" / 483x81328" x 32" / 711x81317.5" x 34" / 445x86426" x 34" / 660x864
Low Pressure Cylinders (dia x stroke) (in / mm)32" x 32" / 813x81330" x 34" / 762x864
Tractive Effort (lbs / kg)60,115 / 27267.7453,493 / 24264.0571,083 / 32242.7452,133 / 23647.1661,694 / 27983.96
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.78 4.45 3.33 4.45 3.86
Heating Ability
Firebox Area (sq ft / m2)298.50 / 33.21234.20 / 21.76234.20 / 21.76205.40 / 19.09206 / 19.14
Grate Area (sq ft / m2)64.70 / 6.0158.50 / 5.4358.50 / 5.4359.50 / 5.5359.50 / 5.53
Evaporative Heating Surface (sq ft / m2)3159 / 293.595390 / 500.743888 / 361.204682 / 435.133730 / 346.53
Superheating Surface (sq ft / m2)721 / 64.41850 / 78.97854 / 79.34
Combined Heating Surface (sq ft / m2)3880 / 3585390 / 500.744738 / 440.174682 / 435.134584 / 425.87
Evaporative Heating Surface/Cylinder Volume185.34513.28170.48494.65178.53
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation13,91112,28511,11513,38810,710
Same as above plus superheater percentage16,55312,28513,11613,38812,745
Same as above but substitute firebox area for grate area76,37149,18252,50846,21544,125
Power L113,350439410,059438710,186
Power MT648.10203.68467.85208.44470.98

Reference