Southern 4-4-2 "Atlantic" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class C (Locobase 110)

Some data from Southern Railway diagrams hosted on (viewed September 2002). Alco builder numbers 39318-39327.

Not considered especially brilliant engines (e.g., Roberts and Schafer in Drury (1993) called them "fleet but feeble.") The Southern built no more Atlantics. Engine #1907 was rebuilt with a superheater and piston valves (Universal steam chest type that were mounted directly on the slide valve base).

Prince (1965) confirms their relatively low pulling power by noting that after steel passenger coaches were introduced, the C class operated eastward out of Macon, Georgia to the lowland areas and such cities as Jessop and Brunswick.

NB: The direct heating surface (including the firebox heating surface) is an estimate calculated by subtracting the calculated tube heating surface from the reported total evaporative heating surface from the baldwin_steam site.

Specifications by Steve Llanso of Sweat House Media
Locobase ID110
RailroadSouthern (SRS)
Number in Class10
Road Numbers1905-1914
Number Built10
Valve GearSouthern
Locomotive Length and Weight
Driver Wheelbase 7.50'
Engine Wheelbase29.50'
Ratio of driving wheelbase to overall engine wheebase 0.25
Overall Wheelbase (engine & tender)51.30'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers108000 lbs
Engine Weight190000 lbs
Tender Light Weight147000 lbs
Total Engine and Tender Weight337000 lbs
Tender Water Capacity7500 gals
Tender Fuel Capacity (oil/coal)12.5 tons
Minimum weight of rail (calculated)90 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter79"
Boiler Pressure200 psi
Cylinders (dia x stroke)20.5" x 26"
Tractive Effort23513 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.59
Heating Ability
Firebox Area183 sq. ft
Grate Area45 sq. ft
Evaporative Heating Surface3113 sq. ft
Superheating Surface
Combined Heating Surface3113 sq. ft
Evaporative Heating Surface/Cylinder Volume313.42
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9000
Same as above plus superheater percentage9000
Same as above but substitute firebox area for grate area36600
Power L110679
Power MT435.98


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