Minneapolis, St Paul & Sault Ste Marie 2-6-2 "Prairie" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class J (Locobase 8741)

Data from Soo Miscellaneous Steam Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

These were the only Prairies to be bought by the Soo and they were pretty rare birds. They arrived as cross-compounds. Both cylinders had 26" strokes; the HP cylinder diameter measured 22", the LP a lusty 35" across. At some later date, these engines were simpled and superheated; those dimensions are shown in the specs.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID8741
RailroadMinneapolis, St Paul & Sault Ste Marie (Soo)
Number in Class10
Road Numbers800-809
Number Built10
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)11.33 / 3.45
Engine Wheelbase (ft / m)20.25 / 6.17
Ratio of driving wheelbase to overall engine wheebase 0.56
Overall Wheelbase (engine & tender) (ft / m)55.67 / 16.97
Axle Loading (Maximum Weight per Axle) (lbs / kg)48,760 / 22,117
Weight on Drivers (lbs / kg)132,760 / 60,219
Engine Weight (lbs / kg)181,320 / 82,245
Tender Loaded Weight (lbs / kg)128,810 / 58,427
Total Engine and Tender Weight (lbs / kg)310,130 / 140,672
Tender Water Capacity (gals / ML)6000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)10 / 9.10
Minimum weight of rail (calculated) (lb/yd / kg/m)74 / 37
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)63 / 1600
Boiler Pressure (psi / kPa)185 / 12.80
High Pressure Cylinders (dia x stroke) (in / mm)22.5" x 26" / 572x660
Tractive Effort (lbs / kg)32,854 / 14902.34
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.04
Heating Ability
Firebox Area (sq ft / m2)165 / 15.33
Grate Area (sq ft / m2)38.36 / 3.57
Evaporative Heating Surface (sq ft / m2)1716 / 159.48
Superheating Surface (sq ft / m2)347 / 32.25
Combined Heating Surface (sq ft / m2)2063 / 191.73
Evaporative Heating Surface/Cylinder Volume143.42
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation7097
Same as above plus superheater percentage8303
Same as above but substitute firebox area for grate area35,714
Power L19195
Power MT458.08

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