G class were known simply as "Big Mallies." Calculated compound tractive effort was 122,683 lb. Purchase stimulated by success of 0-6-6-0s. Low-pressure, 41-in diameter pistons contained a volume of 24.44 cu ft each.
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 (11.8 in a combustion chamber.
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.
Calculated compound tractive effort was 110,400 lb or, using the ARA method, 103,700 lb. BDF, GDF calculated from ARA compound TE. Low-pressure, 41-in diameter pistons contained a volume of 24.44 cu ft each.
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.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Kansas City Southern (KCS)||Kansas City Southern (KCS)||Kansas City Southern (KCS)|
|Number in Class||7||10||8|
|Road Numbers||750-756||757-766||752, 757-759,762,764,766|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.31||0.31||0.31|
|Overall Wheelbase (engine & tender)||84.70'||84.70'||84.70'|
|Axle Loading (Maximum Weight per Axle)||61700 lbs|
|Weight on Drivers||466000 lbs||474000 lbs||476400 lbs|
|Engine Weight||495000 lbs||503000 lbs||507300 lbs|
|Tender Light Weight||218900 lbs||206000 lbs||206000 lbs|
|Total Engine and Tender Weight||713900 lbs||709000 lbs||713300 lbs|
|Tender Water Capacity||10000 gals||10500 gals||10500 gals|
|Tender Fuel Capacity (oil/coal)||4266 gals||4000 gals||4266 gals|
|Minimum weight of rail (calculated)||97 lb/yard||99 lb/yard||99 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||210 psi||225 psi||250 psi|
|High Pressure Cylinders (dia x stroke)||26" x 32"||26" x 32"||22.5" x 32"|
|Low Pressure Cylinders (dia x stroke)||41" x 32" (2)||41" x 32" (2)|
|Tractive Effort||96627 lbs||103529 lbs||120789 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.82||4.58||3.94|
|Firebox Area||454 sq. ft||414 sq. ft||371.50 sq. ft|
|Grate Area||88.30 sq. ft||88.30 sq. ft||88.31 sq. ft|
|Evaporative Heating Surface||5231 sq. ft||5170 sq. ft||5304 sq. ft|
|Superheating Surface||1434 sq. ft||1459 sq. ft||1459 sq. ft|
|Combined Heating Surface||6665 sq. ft||6629 sq. ft||6763 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||266.02||262.92||180.09|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||18543||19868||22078|
|Same as above plus superheater percentage||22622||24238||26935|
|Same as above but substitute firebox area for grate area||116315||113643||113308|