Schenectady 4-4-0 "American" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 2 (Locobase 8402)

Data from William FM Goss, High Steam-Pressures in Locomotive Service, (Washington, DC: Carnegie Institution of Washington, 1907).

Although Schenectady originally delivered this engine in 1897, snags and delays prevented actual testing of the effect of higher pressures on economy and performance until a grant was awarded in 1904 by the Carnegie Institute. This locomotive then was thoroughly tested.

Results indicated that as a saturated-steam locomotive boiler was pressed beyond 200 pounds, the percentage decrease in consumption as pressure increased was less than a commensurate increase at lower pressures. In other words, boiler pressure represented the same kind of barrier to increased economy in locomotive boilers as would the speed of sound to aircraft in a later decade. The solution for locomotives lay in superheating the steam, which was just then taking hold in several countries around the world.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID8402
Number in Class1
Road Numbers2
Number Built1
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 8.50 / 2.59
Engine Wheelbase (ft / m)23 / 7.01
Ratio of driving wheelbase to overall engine wheelbase 0.37
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)61,000 / 27,669
Engine Weight (lbs / kg)109,000 / 49,442
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)51 / 25.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)69.50 / 1765
Boiler Pressure (psi / kPa)240 / 16.50
High Pressure Cylinders (dia x stroke) (in / mm)16" x 24" / 406x610
Tractive Effort (lbs / kg)18,034 / 8180.09
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.38
Heating Ability
Tubes (number - dia) (in / mm)200 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)11.50 / 3.51
Firebox Area (sq ft / m2)126 / 11.71
Grate Area (sq ft / m2)17 / 1.58
Evaporative Heating Surface (sq ft / m2)1322 / 122.86
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1322 / 122.86
Evaporative Heating Surface/Cylinder Volume236.49
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4080
Same as above plus superheater percentage4080
Same as above but substitute firebox area for grate area30,240
Power L19708
Power MT701.72

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Wes Barris