Clover Valley Lumber 2-6-6-2 "Mallet Mogul" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 4 (Locobase 4053)

Data from [], supplemented by DeGolyer, Vol 73, pp. 247+. See also C R Heimerdinger, "California's Baldwin Logging Mallets", Pacific News (March 1979) archived by at [] . Works number was 57684 in March 1924.

Like many of the logging locomotives supplied by Baldwin, this engine had split saddletanks on the boiler (one over each engine unit), which shortened the engine's wheelbase. In fact, this was the very first of the type to be delivered. The superheated boiler's steam was admitted through 8" (203 mm) piston valves to the HP cylinders and 12" (305 mm) piston valves to the larger LP cylinders.

This engine stayed with Clover Valley at Loyalton, Calif until 1956, when the Feather River Lumber Company took over the road and operated #4 for two more years before she went into semi-retirement as a stationary boiler for the Tahoe Timber Company. She ran on the Castro Point Railway in California for 7 years (1979-1986), after which she was stored in Fremont, CA.

Principal Dimensions by Steve Llanso of Middle Run Media

Locobase ID4053
RailroadClover Valley Lumber
Number in Class1
Road Numbers4
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)16 / 4.88
Engine Wheelbase (ft / m)37.75 / 11.51
Ratio of driving wheelbase to overall engine wheelbase 0.42
Overall Wheelbase (engine & tender) (ft / m)37.75 / 11.51
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)182,000 / 82,554
Engine Weight (lbs / kg)219,000 / 99,337
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)219,000
Tender Water Capacity (gals / ML)2500 / 9.47
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)1200 / 4542
Minimum weight of rail (calculated) (lb/yd / kg/m)51 / 25.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)45 / 1143
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)17" x 24" / 432x610
Low Pressure Cylinders (dia x stroke) (in / mm)26" x 24" / 660x610
Tractive Effort (lbs / kg)36,711 / 16651.85
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.96
Heating Ability
Tubes (number - dia) (in / mm)124 - 2" / 51
Flues (number - dia) (in / mm)18 - 5.375" / 137
Flue/Tube length (ft / m)17 / 5.18
Firebox Area (sq ft / m2)128 / 11.89
Grate Area (sq ft / m2)26.20 / 2.43
Evaporative Heating Surface (sq ft / m2)1654 / 153.72
Superheating Surface (sq ft / m2)358 / 33.27
Combined Heating Surface (sq ft / m2)2012 / 186.99
Evaporative Heating Surface/Cylinder Volume262.46
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 area30,208
Power L15610
Power MT407.73

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Wes Barris