Coos Bay Lumber Company 2-8-2 "Mikado" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 104 (Locobase 15234)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 71, pp. 341+. See also the Oregon Coast chapter of the National Railway Historical Society's description of the 104 at [], last accessed 4 June 2013. Works number was 55480 in June 1922.

Essentially a sister to the Pacific States 9 shown in Locobase 15233, the 104 was also a superheated logging Mikado, but burned oil fuel instead of coal and operated on the Coos Bay in Powers, Oregon. The railroad featured 60 lb/yard (30 kg/metre) rail arcing around relatively gentle 11 degree (radii of 521 ft/159 m) curves and climbing ruling grades of 2%. This engine had 8" (203 mm) piston valves.

Like many such engines, the 104 enjoyed a long career, passing to Coos Bay's successor Georgia Pacific in 1956 as their 3. The engine was donated to the Coos-Curry Pioneer & Historical Association in 1960 and was put on display. The OCHR began restoring the 104 in the late 1990s and eventually moved the 104 to a new location.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID15234
RailroadCoos Bay Lumber Company
Number in Class1
Road Numbers104
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12 / 3.66
Engine Wheelbase (ft / m)27.58 / 8.41
Ratio of driving wheelbase to overall engine wheebase 0.44
Overall Wheelbase (engine & tender) (ft / m)50.79 / 15.48
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)116,500 / 52,844
Engine Weight (lbs / kg)145,500 / 65,998
Tender Loaded Weight (lbs / kg)93,000 / 42,184
Total Engine and Tender Weight (lbs / kg)238,500 / 108,182
Tender Water Capacity (gals / ML)4200 / 15.91
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)1600 / 6.10
Minimum weight of rail (calculated) (lb/yd / kg/m)49 / 24.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)44 / 1118
Boiler Pressure (psi / kPa)185 / 12.80
High Pressure Cylinders (dia x stroke) (in / mm)18" x 24" / 457x610
Tractive Effort (lbs / kg)27,790 / 12605.35
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.19
Heating Ability
Firebox Area (sq ft / m2)141 / 13.10
Grate Area (sq ft / m2)25.50 / 2.37
Evaporative Heating Surface (sq ft / m2)1576 / 146.41
Superheating Surface (sq ft / m2)328 / 30.47
Combined Heating Surface (sq ft / m2)1904 / 176.88
Evaporative Heating Surface/Cylinder Volume222.96
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4718
Same as above plus superheater percentage5519
Same as above but substitute firebox area for grate area30,519
Power L110,044
Power MT760.28

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Wes Barris