Weyerhaeuser Timber 2-8-8-2 "Chesapeake" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 200 (Locobase 4046)

Data from [] and DeGolyer, Vol 80, pp. 373. Works number was 60837 in May 1929 and 61753 in 1933. Price in 1929 was $63,637.

Although relatively small for the wheel arrangement, this pair of Mikado Mallets were comparative behemoths on a logging road that used 60 lb/yard (30 kg/metre) rail, scaled 4% grades, and negotiate curves of up to 25 degrees. The HP cylinders were cast separately and attached to an intermediate saddle of cast steel while the LP cylinders were cast integrally with half saddles and bolted together at the center. Locobase suspects that Weyerhaeuser thought the HP cylinders were subject to too much stress to use the more common cylinder-half saddle casting method. All four cylinders got their steam through 12" (305 mm) piston valves.

Both operated in Washington State until scrapped in 1953.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID4046
RailroadWeyerhaeuser Timber
Number in Class2
Road Numbers200-201
Number Built2
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.50 / 4.11
Engine Wheelbase (ft / m)35.75 / 10.90
Ratio of driving wheelbase to overall engine wheebase 0.38
Overall Wheelbase (engine & tender) (ft / m)50 / 15.24
Axle Loading (Maximum Weight per Axle) (lbs / kg)40,000 / 18,144
Weight on Drivers (lbs / kg)320,000 / 145,150
Engine Weight (lbs / kg)355,000 / 161,025
Tender Loaded Weight (lbs / kg)143,000 / 64,864
Total Engine and Tender Weight (lbs / kg)498,000 / 225,889
Tender Water Capacity (gals / ML)7000 / 26.52
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)2500 / 9.50
Minimum weight of rail (calculated) (lb/yd / kg/m)67 / 33.50
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)23" x 28" / 584x711
Low Pressure Cylinders (dia x stroke) (in / mm)35" x 28" / 889x711
Tractive Effort (lbs / kg)74,137 / 33628.02
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.32
Heating Ability
Firebox Area (sq ft / m2)290 / 26.95
Grate Area (sq ft / m2)64.50 / 5.99
Evaporative Heating Surface (sq ft / m2)3639 / 338.20
Superheating Surface (sq ft / m2)985 / 91.54
Combined Heating Surface (sq ft / m2)4624 / 429.74
Evaporative Heating Surface/Cylinder Volume270.27
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation13,868
Same as above plus superheater percentage16,780
Same as above but substitute firebox area for grate area75,444
Power L18179
Power MT450.79

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