Atlanta, Birmingham & Atlantic 4-6-2 "Pacific" Locomotives in 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 Rail Data Exchange. (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)
CountryUSA
Whyte4-6-2
Number in Class1
Road Numbers79
GaugeStd
Number Built
BuilderAlco
Year1913
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.33 / 3.76
Engine Wheelbase (ft / m)23.08 / 7.03
Ratio of driving wheelbase to overall engine wheebase 0.53
Overall Wheelbase (engine & tender) (ft / m)73.50 / 22.40
Axle Loading (Maximum Weight per Axle) (lbs / kg)44,200 / 20,049
Weight on Drivers (lbs / kg)132,600 / 60,146
Engine Weight (lbs / kg)208,500 / 94,574
Tender Loaded Weight (lbs / kg)210,500 / 95,481
Total Engine and Tender Weight (lbs / kg)419,000 / 190,055
Tender Water Capacity (gals / ML)11,000 / 41.67
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)18 / 16.40
Minimum weight of rail (calculated) (lb/yd)74
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)69 / 1753
Boiler Pressure (psi / kPa)210 / 14.50
High Pressure Cylinders (dia x stroke) (in / mm)22" x 26" / 559x660
Tractive Effort (lbs / kg)32,554 / 14766.26
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.07
Heating Ability
Firebox Area (sq ft / m2)160 / 14.87
Grate Area (sq ft / m2)46.90 / 4.36
Evaporative Heating Surface (sq ft / m2)2111 / 196.19
Superheating Surface (sq ft / m2)442 / 41.08
Combined Heating Surface (sq ft / m2)2553 / 237.27
Evaporative Heating Surface/Cylinder Volume184.54
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9849
Same as above plus superheater percentage11,523
Same as above but substitute firebox area for grate area39,312
Power L114,544
Power MT725.43

Reference