Chicago Great Western 2-6-6-2 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class H1 (Locobase 3091)

Data from DeGolyer, Volume 35, p. 176 and Railway Age (30 October 1914). Works numbers were 35365-35374 in October 1910.

Firebox heating surface included 25 sq ft of "water tubes."

The design was essentially identical to the Western Maryland M-1a engines produced in the same month; see Locobase 13938.

After March 1914 tests among ten each of the CGW's Consolidations, these Mallets, and the newer Mikados over the Eastern Division between Oelwein, Iowa and Stockton, Ill, the Railway Age summarized the Prairie Mallet's performance: "It is surprising to note the relatively small amount of gross tons per mile for the Mallet locomotives with such a high percentage of gross to potential ton miles." It isn't surprising, therefore, to find these engines moving on to the Clinchfield by 1916. The CGW simply found the Mikados they were buying more suitable to their requirements.

Picked up by the Clinchfield after the Chicago Great Western found them unsuitable, they lasted only a few years. As Drury (1993) comments: "Their early retirement in 1925 is probably a good indication of their performance."

Specifications by Steve Llanso of Sweat House Media
Locobase ID3091
RailroadChicago Great Western (CGW)
Number in Class10
Road Numbers600-609
Number Built10
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)10
Engine Wheelbase (ft)45.33
Ratio of driving wheelbase to overall engine wheebase 0.22
Overall Wheelbase (engine & tender) (ft)72
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)307,000
Engine Weight (lbs)353,100
Tender Loaded Weight (lbs)146,900
Total Engine and Tender Weight (lbs)500,000
Tender Water Capacity (gals)8000
Tender Fuel Capacity (oil/coal) (gals/tons)15
Minimum weight of rail (calculated) (lb/yd)85
Geometry Relating to Tractive Effort
Driver Diameter (in)57
Boiler Pressure (psi)205
High Pressure Cylinders (dia x stroke) (in)23" x 32"
Low Pressure Cylinders (dia x stroke) (in)35" x 32"
Tractive Effort (lbs)72,284
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.25
Heating Ability
Firebox Area (sq ft)250
Grate Area (sq ft)78
Evaporative Heating Surface (sq ft)5789
Superheating Surface (sq ft)
Combined Heating Surface (sq ft)5789
Evaporative Heating Surface/Cylinder Volume376.20
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation15,990
Same as above plus superheater percentage15,990
Same as above but substitute firebox area for grate area51,250
Power L13847
Power MT165.76


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