Western Maryland 4-4-0 "American" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class D-8 (Locobase 10788)

Data from Baldwin Locomotive Works, Record of Recent Construction ((1903), No. 39, p.268-269 Works numbers were 20755-20756 in August 1902.

This pair of Americans was suited to the WM's mountainous profiles and served the line for 30 years before being scrapped in 1935 (52) and 1936 (51).

Specifications by Steve Llanso of Sweat House Media
Locobase ID10788
RailroadWestern Maryland (WM)
Number in Class2
Road Numbers93-94 / 51-52
Number Built2
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase 7.50'
Engine Wheelbase21.58'
Ratio of driving wheelbase to overall engine wheebase 0.35
Overall Wheelbase (engine & tender)45.75'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers67165 lbs
Engine Weight104785 lbs
Tender Light Weight65215 lbs
Total Engine and Tender Weight170000 lbs
Tender Water Capacity3300 gals
Tender Fuel Capacity (oil/coal)
Minimum weight of rail (calculated)56 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter62"
Boiler Pressure180 psi
Cylinders (dia x stroke)18" x 24"
Tractive Effort19189 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.50
Heating Ability
Firebox Area125 sq. ft
Grate Area29.24 sq. ft
Evaporative Heating Surface1606 sq. ft
Superheating Surface
Combined Heating Surface1606 sq. ft
Evaporative Heating Surface/Cylinder Volume227.20
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5263
Same as above plus superheater percentage5263
Same as above but substitute firebox area for grate area22500
Power L15871
Power MT385.42


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