Seboomook Lake & St John 2-6-2 "Prairie" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 3 (Locobase 15235)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 71, pp. 366+. See also Robert E Pike, Tall Trees, Tough Men (New York, W W Norton, 1967, paperback 1984, reissued 1999) pp. 163-164. Works number was 56606 in May 1923.

A typical Baldwin logging Mikado, this engine used a saturated boiler, the practically universal 44" drivers, and slide valves. Great Northern Paper Company took eight years (1919-1927) to build this 18 mile (29 km) railroad from the headwaters of the St John River in Maine as a way to move pulpwood down river. Pike comments that there must have been "some question from the beginning about the feasibility of this whole project."

History bears out such skepticism: "Not one stick of pulpwood and not a single log was ever hauled over it, and by 1929, those opposed had won out and the rails were taken up." Trucks over gravel road were by then much more useful.

The 3 was quickly sold to Wisconsin Michigan Lumber which then sold it to Rib Lake Lumber northwest of Wausau, one of the biggest loggers in Wisconsin.

Specifications by Steve Llanso of Sweat House Media
Locobase ID15235
RailroadSeboomook Lake & St John
Number in Class1
Road Numbers3
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase10.25'
Engine Wheelbase26.83'
Ratio of driving wheelbase to overall engine wheebase 0.38
Overall Wheelbase (engine & tender)46.54'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers92000 lbs
Engine Weight121000 lbs
Tender Light Weight74000 lbs
Total Engine and Tender Weight195000 lbs
Tender Water Capacity3500 gals
Tender Fuel Capacity (oil/coal)6 tons
Minimum weight of rail (calculated)51 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter44"
Boiler Pressure170 psi
Cylinders (dia x stroke)17" x 24"
Tractive Effort22778 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.04
Heating Ability
Firebox Area101 sq. ft
Grate Area18.90 sq. ft
Evaporative Heating Surface1637 sq. ft
Superheating Surface
Combined Heating Surface1637 sq. ft
Evaporative Heating Surface/Cylinder Volume259.64
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3213
Same as above plus superheater percentage3213
Same as above but substitute firebox area for grate area17170
Power L14235
Power MT304.45

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