Atlanta, Birmingham & Atlantic 4-6-2 "Pacific" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 79 - streamlined (Locobase 7609)

Data from AB&C 11-1930 and AB&C 6 1942 Locomotive Diagrams and Passenger Car Data books supplied in May 2005 by Allen Stanley from his extensive Raildata collection. (Thanks to Chris Hohl for pointing out some semantic problems with the first paragraph.)

When originally sold to the Florida East Coast railroad, the class of Pacifics to which this engine belonged had saturated boilers as shown in Locobase 5716. Several years before they were sold to the AB&C, the class was superheated (Locobase 3138). Then the class was sold to the AB&C.

Most remained relatively unchanged, but the 79 (works# 53908) was streamlined in December 1940 to head up the Dixie Flagler with the results as shown here. Very little on the locomotive was changed, but a skyline casing was added as well as a bullet-tipped smokebox cover. Also, the tender grew considerably and now weighed 210,500 lb (95,481 kg) when loaded with 11,000 US gallons (41,635 litres) of water and 18 tons (16.3 metric tons) of coal.

Specifications by Steve Llanso of Sweat House Media
Class79 - streamlined
Locobase ID7609
RailroadAtlanta, Birmingham & Atlantic (AB&C)
Number in Class1
Road Numbers79
Number Built
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase12.33'
Engine Wheelbase23.08'
Ratio of driving wheelbase to overall engine wheebase 0.53
Overall Wheelbase (engine & tender)73.50'
Axle Loading (Maximum Weight per Axle)44200 lbs
Weight on Drivers132600 lbs
Engine Weight208500 lbs
Tender Light Weight210500 lbs
Total Engine and Tender Weight419000 lbs
Tender Water Capacity11000 gals
Tender Fuel Capacity (oil/coal)18 tons
Minimum weight of rail (calculated)74 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter69"
Boiler Pressure210 psi
Cylinders (dia x stroke)22" x 26"
Tractive Effort32554 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.07
Heating Ability
Firebox Area160 sq. ft
Grate Area46.90 sq. ft
Evaporative Heating Surface2111 sq. ft
Superheating Surface442 sq. ft
Combined Heating Surface2553 sq. ft
Evaporative Heating Surface/Cylinder Volume184.54
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9849
Same as above plus superheater percentage11523
Same as above but substitute firebox area for grate area39312
Power L114544
Power MT725.43


If you have any railroad data such as diagram books, rail station plans or anything else that you would be willing to share, please contact us.