Mount Hood 2-8-2 "Mikado" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 11 (Locobase 14953)

Data from DeGolyer, Vol 65, pp. 198+. See also the trainorders thread that began Works number was 53486 in July 1920 and 55397 in May 1922.

The Oregon Lumber Company owned the MHRR, which operated 22 miles (35.4 km) of logging road in Oregon from Hood River junction on the Union Pacific to Parkdale at the end of the line. Construction began in April 1905 and saw its first train operated in May 1906 to Dee, 16.4 miles (26.4 km) up the line. The last 5.6 miles was opened in January 1, 1910. Rail weights varied from 45 lb/yard (22.5 kg/metre) to 75 and even 100 lb/yard (37.5 and 50 kg/metre).

The class of the road were these two logging Mikados, as they were the newest and best adapted to the demands. A necessary feature was the ability to keep the adhesion weight down to 108,000 lb. If all else failed, said the specs, "throw remainder if possible on trucks." Inspires visions of steel workers carving hunks off frame castings and welding them to the pony trucks. The spec for the 1 (the fourth MHRR engine to wear that number) prescribed 107,000 lb (48,534 kg) adhesion weight even as the tender's capacity grew to 3,500 US gallons (13,248 litres) of water and weight rose to 76,000 lb (34,473 kg).

Steam admission came through 8" (203 mm) piston valves.

In fact, after the MHRR came under the UP's umbrella in 1931, the short line converted the 1 to sod burning. It also trailed an auxiliary wood car. This fact elicited "Jody's" friendly question on the trainorders forum about why this short-line 2-8-2 would need still more fuel than the heaped-up sod in its tender.

Martin ("LoggerHogger") explained: "The line is over 21 miles long and has a killer switchback at the north end. This would use up a lot of fuel wood. The only place the locomotive could get the wood they needed for operation was at the mill at Dee, OR. To give the engine enough range the auxilary tender/flat was used."

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID14,953
RailroadMount Hood
Number in Class2
Road Numbers11, 1
Number Built2
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)48.35 / 14.74
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)108,000 / 48,988
Engine Weight (lbs / kg)144,000 / 65,317
Tender Loaded Weight (lbs / kg)57,500 / 26,082
Total Engine and Tender Weight (lbs / kg)201,500 / 91,399
Tender Water Capacity (gals / ML)2500 / 9.47
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)1500 / 5.70
Minimum weight of rail (calculated) (lb/yd / kg/m)45 / 22.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)44 / 1118
Boiler Pressure (psi / kPa)190 / 13.10
High Pressure Cylinders (dia x stroke) (in / mm)18" x 24" / 457x610
Tractive Effort (lbs / kg)28,541 / 12946.00
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.78
Heating Ability
Firebox Area (sq ft / m2)140 / 13.01
Grate Area (sq ft / m2)25.50 / 2.37
Evaporative Heating Surface (sq ft / m2)1792 / 166.48
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1792 / 166.48
Evaporative Heating Surface/Cylinder Volume253.52
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4845
Same as above plus superheater percentage4845
Same as above but substitute firebox area for grate area26,600
Power L14912
Power MT401.08

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