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, Volume 65, pp. 198-200 and 201-. See also the trainorders thread "Victor & the Vanquished -- Steam to Diesel -- Mt Hood RR", begun by "LoggerHogger" on 22 July 2012, last accessed 26 January 2019 at [],2823991" . See also Clem L Pope, Switchback to the Timber (Hood River, OR: Old Forester Publishing Company, 1992). (Thanks to Steve Low for his 24 January 2019 email questioning Locobase's original chronology, correcting information about fuel changes, and providing a link to Clem Pope's detailed history of the MHRR.) Works numbers were 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 oil-burning logging Mikados, as they were the newest and best adapted to the demands. Clem Pope reported (page 67) that soon after its delivery in September 1920, the 11 "was reported to be able to start ten cars on a 3 1/2% grade. The railroad had never had anything like it, train crews must have thought they died and gone to heaven."

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. The choice of oil-burning meant a straight stack rather than the cabbage stack usually adopted for timber service, and firebrick lining the firebox.

Steve Low pointed Locobase to Clem Pope's history, which notes that "[d]epending on traffic requirements Number 11 would work the mainline haul on the logging road or during the fruit harvest be assigned to the Mount Hood." Balwin produced its virtual twin in 1922; the MHRR gave it number 1.

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

[Locobase note: LoggerHogger's post said the 1 was converted to "sood" [sic] burning and this database's editor chose to conclude that he meant "sod"., perhaps because some western locomotives using lignite fuel were referred to as "dirt-burners." In fact, Steve Low pointed out, it's pretty clear that he meant "wood".)

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID14953
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 wheelbase 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 / Liters/MT)1500 / 5678
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
Tubes (number - dia) (in / mm)263 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)12.08 / 3.68
Firebox Area (sq ft / m2)140 / 13.01
Grate Area (sq ft / m2)25.50 / 2.37
Evaporative Heating Surface (sq ft / m2)1792 / 166.54
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1792 / 166.54
Evaporative Heating Surface/Cylinder Volume253.47
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 L14911
Power MT401.00

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