Georgia Railroad 4-4-2 "Atlantic" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 26/D (Locobase 12159)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 20, p.22. (Thanks to Chris Hohl for his 26 February email and follow-up transmission of a revised diagram, which showed some significant differences between the Baldwin order book and the railroad's operational data.) Works number was 14427-14428 in September 1895.

These were among the first Atlantics to be delivered to any railroad and the only ones the GRR would operate.

Chris Hohl pointed out a key difference between the Baldwin spec and the railroad's diagram, namely the adhesion weight. Baldwin predicted that the weight on the drivers would be 68,000 lb (30,844 kg). As the Locobase entry now shows, the estimate proved more than seven tons too light. A similar shortfall calculated tube heating surface area as considerably less (1,582 sq ft/146.97 sq m) than the actual figure, possibly because the tubes proved to be 6"(152 mm) longer than originally specified..

Less wide of the mark was the engine weight, originally estimated at 120,000 lb (54,431 kg). The diagram also sparked revisions in wheelbase and tender coal capacity.

They were renumbered 501-502 in 1917.

Both were scrapped in 1935.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID12159
RailroadGeorgia Railroad
Number in Class2
Road Numbers26, 36/501-502
Number Built2
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 6.25 / 1.90
Engine Wheelbase (ft / m)23.33 / 7.11
Ratio of driving wheelbase to overall engine wheelbase 0.27
Overall Wheelbase (engine & tender) (ft / m)49.50 / 15.09
Axle Loading (Maximum Weight per Axle) (lbs / kg)41,145 / 18,663
Weight on Drivers (lbs / kg)82,290 / 37,326
Engine Weight (lbs / kg)126,940 / 57,579
Tender Loaded Weight (lbs / kg)80,000 / 36,287
Total Engine and Tender Weight (lbs / kg)206,940 / 93,866
Tender Water Capacity (gals / ML)3500 / 13.26
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)8 / 7
Minimum weight of rail (calculated) (lb/yd / kg/m)69 / 34.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)70 / 1778
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)18" x 24" / 457x610
Tractive Effort (lbs / kg)16,996 / 7709.27
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.84
Heating Ability
Tubes (number - dia) (in / mm)220 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)14.50 / 4.42
Firebox Area (sq ft / m2)135 / 12.54
Grate Area (sq ft / m2)24.80 / 2.30
Evaporative Heating Surface (sq ft / m2)1807 / 167.87
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1807 / 167.87
Evaporative Heating Surface/Cylinder Volume255.59
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4464
Same as above plus superheater percentage4464
Same as above but substitute firebox area for grate area24,300
Power L17372
Power MT395.00

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