Larson Timber 2-6-6-2 "Mallet Mogul" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 14 (Locobase 4044)

Data from and DeGolyer, Vol 73, pp. 280+.Works number was 60256 in November 1927.

This Prairie Mallet for logging service was considerably more powerful than the two earlier 2-6-6-2Ts delivered to Bloedel-Donovan Lumber Mills in 1924 (Locobase 4044). The specs said that this oil-burner would encounter 2% adverse grades when pulling loads, 3 1/2% when hauling empties, all on 70 lb/yard (35 kg/metre) rail and around 24-degree curves (240 feet/73 metre radii). And at the time of its manufacture, 14's railroad included more than 90 miles (145 km) of line.

This later engine's tender was lettered for Bloedel Donovan Lumber Mills before its delivery. (Larson Lumber had merged with BD in 1913.) The engine then went to Port Angeles Western (in Port Angeles, Wash) and then Rayonier, Inc. of Sekiu, Wash.

The 14 was withdrawn in 1964 and scrapped in 1968.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID4044
RailroadLarson Timber
Number in Class1
Road Numbers14
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)9
Engine Wheelbase (ft / m)26.75
Ratio of driving wheelbase to overall engine wheebase 0.34
Overall Wheelbase (engine & tender) (ft / m)65.25
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)250,000
Engine Weight (lbs / kg)275,000 / 131,088
Tender Loaded Weight (lbs / kg)100,000
Total Engine and Tender Weight (lbs / kg)375,000
Tender Water Capacity (gals / ML)5000 / 18.94
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)1500 / 5.70
Minimum weight of rail (calculated) (lb/yd / kg/m)69 / 34.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)51 / 1295
Boiler Pressure (psi / kPa)215 / 14.80
High Pressure Cylinders (dia x stroke) (in / mm)20" x 28" / 508x711
Low Pressure Cylinders (dia x stroke) (in / mm)31" x 28" / 787x711
Tractive Effort (lbs / kg)56,676 / 25707.83
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.41
Heating Ability
Firebox Area (sq ft / m2)198
Grate Area (sq ft / m2)57.20 / 5.30
Evaporative Heating Surface (sq ft / m2)3612
Superheating Surface (sq ft / m2)812
Combined Heating Surface (sq ft / m2)4424
Evaporative Heating Surface/Cylinder Volume354.78
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation12,298
Same as above plus superheater percentage14,512
Same as above but substitute firebox area for grate area50,233
Power L18898
Power MT470.80

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Wes Barris