Potlatch Lumber Company 2-6-6-2 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 24 (Locobase 4060)

Data from http://loggingmallets.railfan.net, supplemented by DeGolyer, Vol 80, pp. 248+ Works number was 59087 in March 1926.

One of several Prairie Mallet tanks built by Baldwin for Northwest logging roads. This full saddle-tanker was delivered to its Idaho operator as a coal burner (using bituminous eggnut Montana round-up coal, according to the specs), but was later converted to oil-burning. Its crown sheet was to be sloped to account for an 8% adverse grade. Rail weight remained at 60 lb/yard (30 kg/metre). HP cylinders were supplied through 8" (203 mm) piston valves, while 12" (305 mm) piston valves fed the LP cylinders.

24 had a cabbage stack for a time while with Potlatch, but it had been removed by the time the engine was sold to Weyerhaeuser in 1931 as #108, where she served first at Elk River, Ida., later at Longview, Wash.

Specifications by Steve Llanso of Sweat House Media
Locobase ID4060
RailroadPotlatch Lumber Company
Number in Class1
Road Numbers24 / 108
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase8'
Engine Wheelbase37.75'
Ratio of driving wheelbase to overall engine wheebase 0.21
Overall Wheelbase (engine & tender)37.75'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers193000 lbs
Engine Weight226000 lbs
Tender Light Weight
Total Engine and Tender Weight226000 lbs
Tender Water Capacity2500 gals
Tender Fuel Capacity (oil/coal)4 tons
Minimum weight of rail (calculated)54 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter44"
Boiler Pressure200 psi
High Pressure Cylinders (dia x stroke)17" x 24"
Low Pressure Cylinders (dia x stroke)26" x 24" (2)
Tractive Effort37545 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.14
Heating Ability
Firebox Area127.40 sq. ft
Grate Area26.20 sq. ft
Evaporative Heating Surface1653 sq. ft
Superheating Surface358 sq. ft
Combined Heating Surface2011 sq. ft
Evaporative Heating Surface/Cylinder Volume262.17
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5240
Same as above plus superheater percentage6183
Same as above but substitute firebox area for grate area30066
Power L15482
Power MT375.72

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