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|
|Railroad||Chicago Great Western (CGW)|
|Number in Class||10|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.22|
|Overall Wheelbase (engine & tender)||72'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||307000 lbs|
|Engine Weight||353100 lbs|
|Tender Light Weight||146900 lbs|
|Total Engine and Tender Weight||500000 lbs|
|Tender Water Capacity||8000 gals|
|Tender Fuel Capacity (oil/coal)||15 tons|
|Minimum weight of rail (calculated)||85 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||205 psi|
|High Pressure Cylinders (dia x stroke)||23" x 32"|
|Low Pressure Cylinders (dia x stroke)||35" x 32" (2)|
|Tractive Effort||72284 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.25|
|Firebox Area||250 sq. ft|
|Grate Area||78 sq. ft|
|Evaporative Heating Surface||5789 sq. ft|
|Combined Heating Surface||5789 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||376.20|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||15990|
|Same as above plus superheater percentage||15990|
|Same as above but substitute firebox area for grate area||51250|