Washington, Idaho & Montana 4-6-0 "Ten-Wheeler" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 1 (Locobase 16529)

Data from American Locomotive Company Negative No. S-440 supplied by Jonathan VanAken. See also Judith Neilsen, "A Brief History of the Washington, Idaho & Montana Railway Company" (1982), Manuscript Group 139, Washington, Idaho & Montana Railway Company, Records, 1903-1962. 65.5 l.f, archived at [], last accessed 7 February 2021; and Washington, Montana, and Idaho History Preservation Group, Inc. website at [], last accessed 7 February 2021. (Many thanks to Jonathan Van Aken for his 3 February 2021 email supplying the builder's negative as well as an extensive account of the WM&I and the #1's career.) Works numbers were 40684-40685 in June 1906.

Tall timber in Idaho's Potlatch Basin led the Wisconsin Log and Lumber Company and Weyerhaeuser to combine efforts as the Potlatch Lumber Company. The original choice for the all-important mill site was Moscow, but lack of water and inflated asking prices led to a relocation 18 miles distant and establishment of Potlatch.

Nielsen's account carefully details all the corporate and railroad negotiations over the next several years, but essentially it always seemed cheaper and quicker for PLC simply to build the 46 mile (74 km) rail line itself. Choosing the three-state name, company president F H Thatcher wrote, avoided a too-local appearance or a misapprehension that the line would be an industrial road. Once construction began in 1905, it moved briskly, laying 20 miles of track to Harvard, Idaho.

(Nielsen commented that some believed stations named Wellesley, Princeton, Harvard, Yale, Stanford, Vassar, Cornell, and Purdue were conceived by young college men. She couldn't confirm, but other than the previously established Princeton, "the story could well be true.")

By the end of 1906, the line had reached Bovil and passenger service hauled by the two Eight-wheelers delivered that year had begun. But the railroad would never extend past Purdue into Montana in large part because the Milwaukee Road and the WM&I agreed to joint use of their tracks with a division of rates. And a major forest fire in 1910 put paid to the plan.

But the WM&I remained independent for decades and Jonathan VanAken notes the 1 and 2's role in its continuing operation. The 1 was "... a capable engine for the short road, and while the Consolidations would typically handle the heavier log trains the Ten-Wheelers proved their worth on early passenger services and general freight haulage. Sometime between their delivery, and the end of their careers in the 1950s, they were superheated and converted to oil firing."

"Between 1950 and 1959", VanAken wrote,"the remaining four locomotives were taken out of service. #2 was scrapped 'in the early 1950s', and #20 & #21 were taken out of service between 1957 and 1959." 1 wound up on display in the city of Potlatch. Eventually, the 1 found cover in the Scenic Six Historical Park, where it remained well into the 21st century.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID16529
RailroadWashington, Idaho & Montana
Number in Class2
Road Numbers1-2
Number Built2
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)14.01 / 4.27
Engine Wheelbase (ft / m)24.57 / 7.49
Ratio of driving wheelbase to overall engine wheelbase 0.57
Overall Wheelbase (engine & tender) (ft / m)52.99 / 16.15
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)115,000 / 52,163
Engine Weight (lbs / kg)152,000 / 68,946
Tender Loaded Weight (lbs / kg)120,599 / 54,703
Total Engine and Tender Weight (lbs / kg)272,599 / 123,649
Tender Water Capacity (gals / ML)6001 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 9.90 / 9
Minimum weight of rail (calculated) (lb/yd / kg/m)64 / 32
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)63 / 1600
Boiler Pressure (psi / kPa)200.20 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)19.02" x 25.98" / 483x660
Tractive Effort (lbs / kg)25,386 / 11514.91
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.53
Heating Ability
Tubes (number - dia) (in / mm)272 - 2.008" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)14.01 / 4.27
Firebox Area (sq ft / m2)152.85 / 14.20
Grate Area (sq ft / m2)27.34 / 2.54
Evaporative Heating Surface (sq ft / m2)2135 / 198.35
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)2135 / 198.35
Evaporative Heating Surface/Cylinder Volume250
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5473
Same as above plus superheater percentage5473
Same as above but substitute firebox area for grate area30,601
Power L17136
Power MT410.40

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