Crown Willamette Paper Co. 2-6-6-2 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 12 (Locobase 4055)

Data from Jon Davis's, supplemented by DeGolyer, Vol 80, pp. 266+. Works number was 60771 in April 1929.

One of several Prairie Mallet tanks built by Baldwin for Northwest logging roads with split saddle tank (called "semi-saddle" in the specifications). Like most of the other tanks of this layout, the HP valves were supplied through 8" (203 mm) piston valves, the LP cylinders through 12" (305 mm) piston valves.

12 worked for 35 years for the same company out of Cathlamet, Wash. She was scrapped after her 1959 retirement.

Specifications by Steve Llanso of Sweat House Media
Locobase ID4055
RailroadCrown Willamette Paper Co.
Number in Class1
Road Numbers12
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase8'
Engine Wheelbase37.25'
Ratio of driving wheelbase to overall engine wheebase 0.21
Overall Wheelbase (engine & tender)37.25'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers183000 lbs
Engine Weight222000 lbs
Tender Light Weight
Total Engine and Tender Weight222000 lbs
Tender Water Capacity2500 gals
Tender Fuel Capacity (oil/coal)1200 gals
Minimum weight of rail (calculated)51 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter44"
Boiler Pressure200 psi
High Pressure Cylinders (dia x stroke)16" x 24"
Low Pressure Cylinders (dia x stroke)26" x 24" (2)
Tractive Effort34436 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.31
Heating Ability
Firebox Area128 sq. ft
Grate Area26.20 sq. ft
Evaporative Heating Surface1654 sq. ft
Superheating Surface358 sq. ft
Combined Heating Surface2012 sq. ft
Evaporative Heating Surface/Cylinder Volume296.15
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 area30208
Power L15486
Power MT396.54

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