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 ID10,788
RailroadWestern Maryland (WM)
Number in Class2
Road Numbers93-94 / 51-52
Number Built2
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft) 7.50
Engine Wheelbase (ft)21.58
Ratio of driving wheelbase to overall engine wheebase 0.35
Overall Wheelbase (engine & tender) (ft)45.75
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)67,165
Engine Weight (lbs)104,785
Tender Loaded Weight (lbs)65,215
Total Engine and Tender Weight (lbs)170,000
Tender Water Capacity (gals)3300
Tender Fuel Capacity (oil/coal) (gals/tons)
Minimum weight of rail (calculated) (lb/yd)56
Geometry Relating to Tractive Effort
Driver Diameter (in)62
Boiler Pressure (psi)180
High Pressure Cylinders (dia x stroke) (in)18" x 24"
Tractive Effort (lbs)19,189
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.50
Heating Ability
Firebox Area (sq ft)125
Grate Area (sq ft)29.24
Evaporative Heating Surface (sq ft)1606
Superheating Surface (sq ft)
Combined Heating Surface (sq ft)1606
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 area22,500
Power L15871
Power MT385.42


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