Wabash 2-6-2 "Prairie" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class G1 - 64" (Locobase 6933)

See also WAB 1 - 1907 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also "Wabash 2-6-2 Fast Freighter", Railroad and Locomotive Engineering, Volume 21, No 2 (February 1908), pp. 54-55. (Thanks to Chris Hohl for his 2 April 2021 email correcting the valve gear information.) Works numbers were 43332-43361 in November 1907.

Railroad Age Gazette (17 July 1908) reported that these locomotives were fast freight Prairies virtually identical to those in service on the CB&Q. Unlike the first 60 (Locobase 4202), these had 64" drivers, which meant they weren't intended for some of the higher-end freight traffic served by the 70" engines.

Like those locomotives, this batch was superheated; see Locobase 6934.


Class G1 - 70" (Locobase 4202)

Data from "Wabash 2-6-2 Fast Freighter", Railway & Locomotive Engineering, Volume 21, No 2 (February 1908), 54-55; "Prairie Locomotive for the Wabash", Railway Age, Volume XLV, No 19 (8 May 1908), pp. 656-657. Railroad Age Gazette (17 July 1908); DeGolyer, Volume 28, pp.260+; and WAB 1907 Locomotive Diagrams supplied in May 1905 by Allen Stanley from his extensive Rail Data Exchange collection. (Thanks to Chris Hohl for noting the correct boiler pressure.) Baldwin's works numbers were 28731-28732, 28780-28781, 28830, 28849-28850, 28865-28866, 28896-28899 in August 1908; 28927-28928, 28941, 28953, 28975, 29006-29007, 29017, 29032-29033, 29057-29059, 29075. 29094, 29166-29167 in September.. Alco-Rogers works numbers were 43302-43331 in September 1907.

RAG reported that these locomotives were fast freight Prairies virtually identical to those in service on the CB&Q (Locobases 1041, 16540, and 2900) ; the latter had 69" drivers. (Drury - 1993 - says the whole Wabash class had 64" drivers, but the first 60, which included the batch described by RAG, had 70" wheels.) Piston valve diameters measured 12" (305 mm) each and the firebox spanned 73" (1,854 mm).

They were reported to have a train load capacity of 1,750-2,100 tons on lines with grades between 0.5-0.85%. RAG noted several features about the design, in particular the trend toward the use of flexible staybolts in great numbers and the provision of leading truck wheels 37 1/2" in diameter. Like many other Walschaert running gear layouts, the designers strove to arrange all the components to move in the same plane.

(Angus Sinclair, editor of the R&LE, was fond of unusual comparisons. To convey the great size of the G1's heating surface area, he described it as equivalent of the area of a circle drawn to a diameter approximately equal to the overall length of the engine and tender (61 ft 4 in/18.69 m).

Of the 60 70" G-1s, 23 became J-2 Pacifics beginning in 1916 (Locobase 6935). The others were superheated as Prairies; see Locobase 6932.

Retirements of the Prairies began in 1934 and ended in 1950.


Class G1s - 64" (Locobase 6934)

Data from WAB 1 - 1907 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

This batch was identical to the earlier G-1s, but had smaller drivers. Like the others, these were superheated beginning in the teens, three having been ministered to by January 1917. By the end of the 1920s, all had been superheated. Firebox heating surface area included 28 sq ft (2.60 sq m) in four arch tubes. Cylnder diameters grew by 1" (25.4 mm) but piston valve diameters remained 12" (305 mm).

The result is a nicely balanced design in Locobase's opinion. The heat generator wasn't overworked and if the max axle loading was a bit high -- well, these were mainline engines. By 1946, surviving engines in this class has boilers pressed to 215 psi (14.83 bar).


Class G1s - 70" (Locobase 6932)

Data from WAB 1 - 1907 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Not long after the Baldwin and Alco-Rogers G-1s went into service (Locobase 4202), railroads became convinced of the value of superheating. In the Wabash's case, they leaped at the chance to apply it to their 2-6-2s. Firebox heating surface area increased with the addition of 28 sq ft (2.60 sq m) in four arch tubes. Each cylinder gained an inch in diameter; piston valve diameters remained 12" (305 mm).

By January 1917 three had already been made over. By the late 1920s 37 of the original 60 had been redone; they retained their 70" drivers. The G-1s consisted of Baldwins 2001-2002, 2005-2006, 2008-2009, 2011-2015, 2017-2018, 2020-2030 and Alco-Rogers 2034, 2036, 2040, 2042-2043, 2046, 2048-2050, and 2057-2060,

The last batch of 30 supplied by Alco in 1907, which had 64" drivers, were also superheated; see Locobase 6933.

Principal Dimensions by Steve Llanso of Middle Run Media

ClassG1 - 64"G1 - 70"G1s - 64"G1s - 70"
Locobase ID6933 4202 6934 6932
RailroadWabashWabashWabashWabash
CountryUSAUSAUSAUSA
Whyte2-6-22-6-22-6-22-6-2
Number in Class30602337
Road Numbers2061-20902001-20602061-20902001+
GaugeStdStdStdStd
Number Built3060
BuilderAlco-RogersseveralWabashWabash
Year1907190719171917
Valve GearStephensonWalschaertStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.37 / 4.0813.37 / 4.0813.37 / 4.0813.37 / 4.08
Engine Wheelbase (ft / m)30.71 / 9.3630.71 / 9.3630.71 / 9.3630.71 / 9.36
Ratio of driving wheelbase to overall engine wheelbase 0.44 0.44 0.44 0.44
Overall Wheelbase (engine & tender) (ft / m)63.35 / 19.3161.35 / 18.7061.35 / 18.7061.35 / 18.70
Axle Loading (Maximum Weight per Axle) (lbs / kg)56,400 / 25,58362,650 / 28,41862,650 / 28,418
Weight on Drivers (lbs / kg)143,100 / 64,909150,500 / 68,266167,900 / 76,158167,900 / 76,158
Engine Weight (lbs / kg)203,100 / 92,125205,900 / 93,395230,100 / 104,372230,100 / 104,372
Tender Loaded Weight (lbs / kg)155,317 / 70,451153,000 / 69,400153,000 / 69,400153,000 / 69,400
Total Engine and Tender Weight (lbs / kg)358,417 / 162,576358,900 / 162,795383,100 / 173,772383,100 / 173,772
Tender Water Capacity (gals / ML)7700 / 29.177700 / 29.176000 / 22.736000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)15 / 1415 / 1410 / 910 / 9
Minimum weight of rail (calculated) (lb/yd / kg/m)80 / 4084 / 4293 / 46.5093 / 46.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)64 / 162670 / 177864 / 162670 / 1778
Boiler Pressure (psi / kPa)200 / 13.80210 / 14.50195 / 13.40210 / 14.50
High Pressure Cylinders (dia x stroke) (in / mm)22" x 28" / 559x71122" x 28" / 559x71123" x 28" / 584x71123" x 28" / 584x711
Tractive Effort (lbs / kg)35,998 / 16328.4434,558 / 15675.2638,361 / 17400.2837,771 / 17132.66
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.98 4.35 4.38 4.45
Heating Ability
Tubes (number - dia) (in / mm)301 - 2" / 51301 - 2.25" / 57164 - 2.25" / 57164 - 2.25" / 57
Flues (number - dia) (in / mm)28 - 5.5" / 14028 - 5.5" / 140
Flue/Tube length (ft / m)19 / 5.7919 / 5.7919 / 5.7919 / 5.79
Firebox Area (sq ft / m2)190.50 / 17.70190.50 / 17.70218 / 20.25218 / 20.25
Grate Area (sq ft / m2)54.25 / 5.0454.25 / 5.0454.25 / 5.0454.25 / 5.04
Evaporative Heating Surface (sq ft / m2)3559 / 330.643559 / 330.642805 / 260.592805 / 260.59
Superheating Surface (sq ft / m2)613 / 56.95613 / 56.95
Combined Heating Surface (sq ft / m2)3559 / 330.643559 / 330.643418 / 317.543418 / 317.54
Evaporative Heating Surface/Cylinder Volume288.88288.88208.40208.40
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,85011,39310,57911,393
Same as above plus superheater percentage10,85011,39312,48313,443
Same as above but substitute firebox area for grate area38,10040,00550,16254,020
Power L17812897214,54517,132
Power MT361.06394.28572.95674.86

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