Minneapolis, St Paul & Sault Ste Marie 4-8-4 "Northern" Type Locomotives

Class O-20 (Locobase 278)

Drury (1993) says of these engines: "Assigned to fast Chicago-Twin Cities freight trains, [they] acquired a reputation for availability -- they were able to turn at the terminals and be on their way quickly."

Note that the superheater area in the specs is estimated. It is a calculation based on taking the diagram value of 2,120 sq ft of "superheater equivalent" and deducting a third from it. See the logic presented in Locobase 1364.

Specifications
ClassO-20
Locobase ID278
RailroadMinneapolis, St Paul & Sault Ste Marie (Soo)
Whyte4-8-4
Road Numbers5000-5003
GaugeStd
BuilderLima
Year1938
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase19.75'
Engine Wheelbase46.75'
Ratio of driving wheelbase to overall engine wheebase 0.42
Overall Wheelbase (engine & tender)87.47'
Axle Loading (Maximum Weight per Axle)65900 lbs
Weight on Drivers263000 lbs
Engine Weight445550 lbs
Tender Light Weight317600 lbs
Total Engine and Tender Weight763150 lbs
Tender Water Capacity17500 gals
Tender Fuel Capacity (oil/coal)24 tons
Minimum weight per yard of rail on which locomotive could run109.58 lb rail
Geometry Relating to Tractive Effort
Driver Diameter75"
Boiler Pressure275 psi
Cylinders (dia x stroke)26" x 32"
Tractive Effort67420 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.90
Heating Ability
Firebox Area423 sq. ft
Grate Area88.30 sq. ft
Evaporative Heating Surface5142
Superheating Surface1413
Combined Heating Surface6555
Evaporative Heating Surface/Cylinder Volume261.49
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation24282.50
Same as above plus superheater percentage29516.85
Same as above but substitute firebox area for grate area141400.09
Power L134916.84
Power MT1170.77

Credits

Introduction and specifications provided by Steve Llanso of Sweat House Media.