Kansas City Southern 2-8-8-0 "Consolidation Mallet" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class G-1 (Locobase 437)

Data confirmed by KCS 1942-2 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Albert F Stuebing, "The Advantages of Large Freight Locomotives, Particularly the 2-10-2 Type", Paper 1795 presented at the Spring Meeting, Chicago, Ill (23-26 May 1921), pp. 325 et seq, esp. the comments of John Muhfeld reporting the KCS's experience with Mallets beginning on p. 335. (Thanks to Chris Hohl for a 26 March 2012 email reporting the low tender capacity originally entered for this entry.) Works numbers were 59108-59114 in 1918.

The G-1/G-2 classes were known simply as "Big Mallies." The KCS measured the G-1s' compound tractive effort as 122,683 lb (55,648 kg). Purchase stimulated by success of 0-6-6-0s. Among John E Muhfeld's many points supporting the value of the KCS's Mallets was a refutation of the claim that Mallets were "difficult and expensive to maintain and that special facilities are required for engine house and back-shop repair work." Rather, he said, the G-1s used regular shop facilities, made "from 80,000 to 85,000 miles[128,800-136,850 km] between classified repairs ...and during busy months will all average as high as 3,500 miles [5,635 km] per locomotive."

Assigned to KCS's Northern Division (KC to De Queen, Ark.). Two later refitted briefly to burn pulverized coal, but reverted to oil burning in 1930. Firebox heating surface included that provided by 92 sq ft (8.55 sq m) in four arch tubes and 127 sq ft (11.80 sq m) in a combustion chamber. Fourteen-inch (356 mm) piston valves fed steam to the HP cylinders, slide valves did for the LP cylinders ahead of the smokebox. Inside dry pipes conveyed steam from the dome to the superheater.

Delivered with the pressure set to 210 psi, 4 of the class -- 755, 752, 754, 750 -- had their settings changed to 220 psi. In 1927, the railroad increased the boiler pressure in 751, 752, 754, and 756 from 220 psi to 240 psi.

See Locobase 438 for the 1923 G-2 class.


Class G-2 (Locobase 438)

Data from KCS 1 - 1942 Locomotive Diagram book supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection. See also "The K C S Railway Co Buys Ten New Engines", Port Arthur Route Agricultural and Industrial Bulletin [a KCS publication], Volume 4, No 8 (July 1923), p. 2; and, more generally, Albert F Stuebing, "The Advantages of Large Freight Locomotives, Particularly the 2-10-2 Type", Paper 1795 presented at the Spring Meeting, Chicago, Ill (23-26 May 1921), pp. 325 et seq, esp. the comments of John Muhfeld reporting the KCS's experience with Mallets beginning on p. 335. Works numbers were 65148-65157 in January 1924.

Developments of the 1918 G-1s (Locobase 437) delivered by Schenectady with only detail differences between the two batches. Each of the ten locomotives cost about $100,000.

According to the KCS report of July 1923, the only significant changes were the adoption of piston valves for the low-pressure cylinders; each of the four valves measured 14" (356 mm) in diameter. The dry pipe carrying steam from the dome to the superheater now appeared outside the boiler cladding. A slight change in tube and flue counts (down eight in tubes, up two in flues) and a boiler pressure increase of 15 psi (1.03 bar), and a slight increase in an already generous superheater proportion of the combined heating surface area were other changes.

As in the G-1s, the G-2s' firebox heating surface area included the 121 sq ft (11.24 sq m) yielded by the combustion chamber and the 52 sq ft (4.83 sq m) in five arch tubes.

The Port Arthur Route said the new design could haul 2,700 tons (2,450 metric tonnes or 50 loaded cars each weighing 50 short tons) over a ruling grade of 1.5% southbound and 1.35% northbound. Each locomotive mile would consume 37 US gallons (140 litres) of fuel oil and 550 gallons (2,082 litres) of water.


Class G-2S (Locobase 308)

Data from http://home.insightbb.com/~sammy56/folio/fo43-11.jpg (August 2002) has the blueprint elevation with all the data, supplemented by KCS 10 - 1950 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for correcting the builder attribution.)

Seven Big Mallies were rebuilt as four-cylinder simple articulateds by the KCS during World War II. Eliminating those massive, 41-inch diameter low-pressure cylinders permitted a speed increase of up to 50%. Firebox heating surface includes 102.5 sq ft (9.5 sq m) of thermic syphons and 28 sq ft (2.6 sq m) of arch tubes. Piston valves measured 12" (306 mm) in diameter. Fitted with a Worthington 6-A feedwater heater.

Although the diagram clearly shows a combustion chamber, its length isn't recorded.

Principal Dimensions by Steve Llanso of Sweat House Media
ClassG-1G-2G-2S
Locobase ID437 438 308
RailroadKansas City Southern (KCS)Kansas City Southern (KCS)Kansas City Southern (KCS)
CountryUSAUSAUSA
Whyte2-8-8-02-8-8-02-8-8-0
Number in Class7108
Road Numbers750-756757-766752, 757-759,762,764,766
GaugeStdStdStd
Number Built710
BuilderAlco-SchenectadyAlco-BrooksKCS
Year191819241943
Valve GearBakerWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.50 / 4.7215.50 / 4.7215.50 / 4.72
Engine Wheelbase (ft / m)50.50 / 15.3950.50 / 15.3950.50 / 15.39
Ratio of driving wheelbase to overall engine wheebase 0.31 0.31 0.31
Overall Wheelbase (engine & tender) (ft / m)84.70 / 25.8284.70 / 25.8284.70 / 25.82
Axle Loading (Maximum Weight per Axle) (lbs / kg)61,700 / 27,98763,000 / 28,576
Weight on Drivers (lbs / kg)466,000 / 211,374476,400 / 216,092476,400 / 216,092
Engine Weight (lbs / kg)495,000 / 224,528507,300 / 230,108507,300 / 230,108
Tender Loaded Weight (lbs / kg)218,900 / 99,291206,000 / 93,440206,000 / 93,440
Total Engine and Tender Weight (lbs / kg)713,900 / 323,819713,300 / 323,548713,300 / 323,548
Tender Water Capacity (gals / ML)10,000 / 3.7910,500 / 39.7710,500 / 39.77
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)4266 / 16.204000 / 15.204266 / 16.20
Minimum weight of rail (calculated) (lb/yd / kg/m)97 / 48.5099 / 49.5099 / 49.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 144857 / 144857 / 1448
Boiler Pressure (psi / kPa)210 / 14.50225 / 15.50250 / 17.20
High Pressure Cylinders (dia x stroke) (in / mm)26" x 32" / 660x81326" x 32" / 660x81322.5" x 32" / 572x813 (4)
Low Pressure Cylinders (dia x stroke) (in / mm)41" x 32" / 1041x81341" x 32" / 1041x813
Tractive Effort (lbs / kg)96,627 / 43829.32103,529 / 46960.02120,789 / 54789.03
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.82 4.60 3.94
Heating Ability
Firebox Area (sq ft / m2)420 / 42.19414 / 38.46371.50 / 34.53
Grate Area (sq ft / m2)88.30 / 8.2188.30 / 8.2088.31 / 8.21
Evaporative Heating Surface (sq ft / m2)5251 / 486.155222 / 485.145304 / 492.94
Superheating Surface (sq ft / m2)1434 / 133.271459 / 135.541459 / 135.59
Combined Heating Surface (sq ft / m2)6685 / 619.426681 / 620.686763 / 628.53
Evaporative Heating Surface/Cylinder Volume267.04265.56180.09
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation18,54319,86822,078
Same as above plus superheater percentage22,43724,23826,935
Same as above but substitute firebox area for grate area106,722113,643113,308
Power L18265892816,364
Power MT312.81330.53605.82

Reference