Virginian Other Articulated Locomotives

Class AA (Locobase 291)

Data from VGN 8 - 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Four-cylinder compound that was not well loved by its fireman because it was hand-bombed and not superheated. All but 503 received both mechanical stokers and superheaters later on. See Locobase 7487

Class AA - superheated (Locobase 7487)

Data from VGN 8 - 1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Four-cylinder compound that was not well loved by its fireman because it was hand-bombed and not superheated. All but 503 received both mechanical stokers and superheaters later on. See Locobase

Class AC (Locobase 3564)

30 sq ft of firebox heating surface came as arch tubes.

Drury (1993) notes that these locomotives were more powerful than many 2-6-6-2s. On slow coal drags, their small drivers, lack of a trailing axle, and large LP cylinders weren't disabilities.

Wiener (1930) gives mixed data, including superheater heating surface but not including the flue tube count or size.

Specifications
Class	AA	AA - superheated	AC
Locobase ID	291	7487	3564
Railroad	Virginian	Virginian	Virginian
Whyte	2-6-6-0	2-6-6-0	2-6-6-0
Road Numbers	500-503	500-502	510-517
Gauge	Std	Std	Std
Builder	Alco-Richmond	shops	Baldwin
Year	1909	1922	1910
Valve Gear	Walschaert	Walschaert
	Locomotive Length and Weight
Driver Wheelbase	11'	11'	10.67'
Engine Wheelbase	39.92'	39.92'	31.18'
Ratio of driving wheelbase to overall engine wheebase	0.28	0.28	0.34
Overall Wheelbase (engine & tender)	72.06'	72.06'	74.70'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers	279900 lbs	295600 lbs	356800 lbs
Engine Weight	295600 lbs	311300 lbs	385300 lbs
Tender Light Weight	172000 lbs	172000 lbs	181700 lbs
Total Engine and Tender Weight	467600 lbs	483300 lbs	567000 lbs
Tender Water Capacity	9500 gals	9500 gals	9500 gals
Tender Fuel Capacity (oil/coal)		15 tons	15 tons
Minimum weight per yard of rail on which locomotive could run	77.75 lb rail	82.11 lb rail	99.11 lb rail
	Geometry Relating to Tractive Effort
Driver Diameter	54"	54"	54"
Boiler Pressure	200 psi	200 psi	210 psi
Cylinders (dia x stroke)	22" x 30"	22" x 30"	24" x 32"
Low Pressure Cylinders (dia x stroke)	35" x 30"	35" x 30"	36" x 32"
Tractive Effort	65531 lbs	65531 lbs	84362 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort)	4.27	4.51	4.23
	Heating Ability
Firebox Area	223 sq. ft	223 sq. ft	264 sq. ft
Grate Area	57 sq. ft	57 sq. ft	78 sq. ft
Evaporative Heating Surface	5046	3855	5641
Superheating Surface		878	742
Combined Heating Surface	5046	4733	6383
Evaporative Heating Surface/Cylinder Volume	382.30	292.07	336.67
	Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation	11400	11400	16380
Same as above plus superheater percentage	11400	13514.77	18284.11
Same as above but substitute firebox area for grate area	44600	52873.57	61884.69
Power L1	3319.63	6935.62	6837.75
Power MT	156.88	310.36	253.50