Clemons Logging Co 2-6-6-2 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 6 (Locobase 4052)

Data from, supplemented by DeGolyer, Vol 71, pp. 226+. See also Clark Kinsey photograph and text at University of Washington Libraries, Special Collections at, last accessed 3 July 2012. Works number was 57601 in January 1924.

Baldwin's mid-1920s offering of an articulated tank with six coupled axles in two groups proved to be a satisfactory combination of power and flexibility for a series of Northwest timber harvesters. Rails weighed a relatively light 60 lb/yard (30 kg/metre), maximum grades often exceeded 4%, and curves could be as tight as 40 degrees.

The basic layout came in several versions that differed in the kinds of water tanks (Clemons #6 had rectangular side tanks), cylinder volumes, and weight.) Like the other Baldwin 2-6-6-2 tanks, the HP cylinders in 7 and 8 used 8" (203 mm) piston valves and LP cylinders were served by 12" (305 mm) piston valves.

The website's photo of #6 is accompanied by a summary of the company's history: "Clemons Logging Company was organized in 1903 ... In 1919, the company was consolidated with the Melbourne and North River Railroad Company, an eight mile logging railroad extending from Melbourne to Montesano. In that same year, the company was reorganized as the Clemons Logging Company, a wholly owned subsidiary of the Weyerhaeuser Timber Company."

Eventually, CLC would run trains over 75 miles (120 km) of logging road. Not quite two decades later, CLC was dissolved on 29 June 1937 as a result of its assets being taken into the parent company.

Clemons would return to Baldwin for a slightly bigger pair of engines in 1925; see Locobase 4051. 6 remained with Weyerhaeuser into the 1950s.

Class 7 (Locobase 4051)

Data from, supplemented by DeGolyer, Vol 80, pp. 286+. See Locobase 3643 for a discussion of the split-saddletank design. Works numbers were 58529 in July 1925 and 60343 in January 1928.

Very similar to the Weyerhaeuser Prairie Mallet tanks, these two were delivered to Clemons in 1925 and 1928. Like the Weyerhaeuser, this design featured split saddletanks on the boiler (one over each engine unit), which shortened the engine's wheelbase. Its HP cylinders were served by 8" (203 mm) piston valves, LPs by 12" (305 mm) piston valves. The 7 and 8 rolled on 60 lb/yard (30 kg/ metre) rails and were confronted with 4% adverse grades in the empty (i.e. back to the forest) direction while loaded cars faced only a 1% grade.

Specifications by Steve Llanso of Sweat House Media
Locobase ID4052 4051
RailroadClemons Logging CoClemons Logging Co
Number in Class12
Road Numbers67-8
Number Built12
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)88
Engine Wheelbase (ft)37.7537.75
Ratio of driving wheelbase to overall engine wheebase 0.21 0.21
Overall Wheelbase (engine & tender) (ft)37.7537.75
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)182,000200,000
Engine Weight (lbs)220,000238,000
Tender Loaded Weight (lbs)
Total Engine and Tender Weight (lbs)220,000238,000
Tender Water Capacity (gals)25002500
Tender Fuel Capacity (oil/coal) (gals/tons)10001000
Minimum weight of rail (calculated) (lb/yd)5156
Geometry Relating to Tractive Effort
Driver Diameter (in)4444
Boiler Pressure (psi)200200
High Pressure Cylinders (dia x stroke) (in)17" x 24"18" x 24"
Low Pressure Cylinders (dia x stroke) (in)26" x 24"28" x 24"
Tractive Effort (lbs)37,54542,517
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.85 4.70
Heating Ability
Firebox Area (sq ft)128128
Grate Area (sq ft)26.2026.20
Evaporative Heating Surface (sq ft)16541654
Superheating Surface (sq ft)358358
Combined Heating Surface (sq ft)20122012
Evaporative Heating Surface/Cylinder Volume262.33233.99
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation52405240
Same as above plus superheater percentage61836183
Same as above but substitute firebox area for grate area30,20830,208
Power L154864730
Power MT398.72312.84

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