Southern Aluminum Company 2-6-2 "Prairie" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 2 (Locobase 14081)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 45, p. 260. See also Locobase 14080 for a short history of the SAC. Works number was 41163 in February 1914.

The differences between the recently delivered 1 (Locobase 14080) and the 2 shown here suggest an adjustment in expectations in favor of much heavier traffic over much tighter alignments. A special note in the specs states that the travel of the two auxiliary trucks needed to be changed to accommodate 40-degree curves (i.e., with radii as tight as 146 feet/44.5 metres). As the extra driven axle implies, everything else was bigger and heavier as well, although the grate grew only a little and thus showed a high ratio between heating surface area and the grate.

The 2 later went to the Deer Park Lumber Company of Deer Park, Wash, then to the West Fork Logging Company of Tacoma. West Fork's operations, owned by T J Murray, were sold in 1943 to the St Regis Paper Company. This transaction included the 2, which served St Regis until it was scrapped in March 1952.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID14,081
RailroadSouthern Aluminum Company
Number in Class1
Road Numbers2
Number Built1
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)10 / 3.05
Engine Wheelbase (ft / m)26.50 / 8.08
Ratio of driving wheelbase to overall engine wheebase 0.38
Overall Wheelbase (engine & tender) (ft / m)26.50 / 8.08
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)110,000 / 49,895
Engine Weight (lbs / kg)148,000 / 67,132
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)148,000
Tender Water Capacity (gals / ML)2500 / 9.47
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)61 / 30.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)44 / 1118
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)17" x 24" / 432x610
Tractive Effort (lbs / kg)24,118 / 10939.75
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.56
Heating Ability
Firebox Area (sq ft / m2)105 / 9.75
Grate Area (sq ft / m2)15.80 / 1.47
Evaporative Heating Surface (sq ft / m2)1587 / 147.44
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1587 / 147.44
Evaporative Heating Surface/Cylinder Volume251.70
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2844
Same as above plus superheater percentage2844
Same as above but substitute firebox area for grate area18,900
Power L14422
Power MT265.88

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Wes Barris