When these came on the line in 1913, they were among the biggest articulateds in the world. Certainly their LP cylinders were huge. Even for coal traffic, the ADs must have been a little slow and the railroad scrapped them in the 1930s while retaining the USRA Mallet Consolidation designs and the 2-10-10-2s.
After the 2-8-8-8-4 Triplex had proved a flat-footed failure, Baldwin took the huge boiler and placed in 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.
The single AF soon acquired a trailing truck and the engine shown above operated until 1953.
| Specifications | |||
|---|---|---|---|
| Class | AB | AD | Triplex reborn - AF |
| Locobase ID | 3565 | 3567 | 3566 |
| Railroad | Virginian | Virginian | Virginian |
| Whyte | 2-8-8-2 | 2-8-8-2 | 2-8-8-2 |
| Road Numbers | 610 | 601-606 | |
| Gauge | Std | Std | Std |
| Builder | Baldwin | Alco-Richmond | Baldwin |
| Year | 1910 | 1913 | 1920 |
| Valve Gear | Walschaert | Walschaert | Walschaert |
| Locomotive Length and Weight | |||
| Driver Wheelbase | 15' | 15.50' | 15.25' |
| Engine Wheelbase | 58.17' | 57.33' | 50.50' |
| Ratio of driving wheelbase to overall engine wheebase | 0.26 | 0.27 | 0.30 |
| Overall Wheelbase (engine & tender) | 89.20' | 99.82' | 90.92' |
| Axle Loading (Maximum Weight per Axle) | |||
| Weight on Drivers | 405400 lbs | 475000 lbs | 487400 lbs |
| Engine Weight | 448750 lbs | 540000 lbs | 526190 lbs |
| Tender Light Weight | 176250 lbs | 212000 lbs | 235000 lbs |
| Total Engine and Tender Weight | 625000 lbs | 752000 lbs | 761190 lbs |
| Tender Water Capacity | 9500 gals | 12000 gals | 13000 gals |
| Tender Fuel Capacity (oil/coal) | 12 tons | 16 tons | 12 tons |
| Minimum weight per yard of rail on which locomotive could run | 84.46 lb rail | 98.96 lb rail | 101.54 lb rail |
| Geometry Relating to Tractive Effort | |||
| Driver Diameter | 56" | 56" | 56" |
| Boiler Pressure | 210 psi | 200 psi | 200 psi |
| Cylinders (dia x stroke) | 26" x 32" | 28" x 32" | 28" x 32" |
| Low Pressure Cylinders (dia x stroke) | 40" x 32" | 44" x 32" | 44" x 32" |
| Tractive Effort | 96945 lbs | 108416 lbs | 108416 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.18 | 4.38 | 4.50 |
| Heating Ability | |||
| Firebox Area | 298 sq. ft | 447 sq. ft | 430 sq. ft |
| Grate Area | 84 sq. ft | 99.20 sq. ft | 108.20 sq. ft |
| Evaporative Heating Surface | 6926 | 6909 | 8120 |
| Superheating Surface | 1311 | 2059 | |
| Combined Heating Surface | 6926 | 8220 | 10179 |
| Evaporative Heating Surface/Cylinder Volume | 352.22 | 302.95 | 356.05 |
| Computations Relating to Power Output (More Information) | |||
| Robert LeMassena's Power Computation | 17640 | 19840 | 21640 |
| Same as above plus superheater percentage | 17640 | 23004.26 | 26017.32 |
| Same as above but substitute firebox area for grate area | 62580 | 103658.32 | 103396.01 |
| Power L1 | 3544.18 | 6941.83 | 9546.47 |
| Power MT | 154.19 | 257.75 | 345.45 |
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