Virginian 2-8-8-0 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class Triplex reborn - AF (Locobase 3566)

Data from VGN 8 - 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Volume 68, pp. 377+. Works number was 55100 in September 1921.

After the 2-8-8-8-4 Triplex had proved a flat-footed failure (Locobase 3301), Baldwin took the huge boiler and placed it on a 2-8-8-0 engine unit. The cylinders matched those of the 1913 ADs, but the tube and flue layout remained that of the Triplex boiler. Firebox heating surface included 72 sq ft (6.7 sq m) of arch tubes. The firebox also had a Gaines combustion chamber and was fed by a Duplex automatic stoker. The resulting combination of boiler and superheater put the AF in a very small class of steam locomotives with over 10,000 sq ft (929 sq m) of combined heating surface.

The high-pressure cylinders powering the rear driver set were fed by 16" (406 mm) piston valves while the low-pressure cylinders under the smokebox were supplied by Allen-Richardson balanced slide valves.

The ruling grade for AF service was the 12 mile (19.3 km) portion of the Elmore to Clark's Gap segment that inclined at 2.07%. The single AF gained a trailing truck in November 1942 to become a 2-8-8-2 and operated until 1953.

Specifications by Steve Llanso of Sweat House Media
ClassTriplex reborn - AF
Locobase ID3566
RailroadVirginian (VGN)
Number in Class1
Road Numbers610
Number Built1
Valve GearBaker
Locomotive Length and Weight
Driver Wheelbase15.25'
Engine Wheelbase50.50'
Ratio of driving wheelbase to overall engine wheebase 0.30
Overall Wheelbase (engine & tender)90.92'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers487400 lbs
Engine Weight526190 lbs
Tender Light Weight235000 lbs
Total Engine and Tender Weight761190 lbs
Tender Water Capacity13000 gals
Tender Fuel Capacity (oil/coal)12 tons
Minimum weight of rail (calculated)102 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter56"
Boiler Pressure200 psi
High Pressure Cylinders (dia x stroke)28" x 32"
Low Pressure Cylinders (dia x stroke)44" x 32" (2)
Tractive Effort108416 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.50
Heating Ability
Firebox Area430 sq. ft
Grate Area108.20 sq. ft
Evaporative Heating Surface8120 sq. ft
Superheating Surface2059 sq. ft
Combined Heating Surface10179 sq. ft
Evaporative Heating Surface/Cylinder Volume356.05
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation21640
Same as above plus superheater percentage25968
Same as above but substitute firebox area for grate area103200
Power L19546
Power MT345.43

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