One notable feature of this design was the widely spread drivers, which allowed a long, narrow firebox to be fit between the frames and the axles. The last of the class was dismantled in January 1926.
| Specifications | ||
|---|---|---|
| Class | A-2 | A-4 |
| Locobase ID | 8495 | 8496 |
| Railroad | New Orleans Pacific (T & P) | Texas & Pacific (T & P) |
| Whyte | 4-4-0 | 4-4-0 |
| Road Numbers | 117-123 | 186-188 |
| Gauge | Std | Std |
| Builder | Danforth, Cooke | New York |
| Year | 1882 | 1887 |
| Valve Gear | Stephenson | Stephenson |
| Locomotive Length and Weight | ||
| Driver Wheelbase | 8' | 9.37' |
| Engine Wheelbase | 21.83' | 23.73' |
| Ratio of driving wheelbase to overall engine wheebase | 0.37 | 0.39 |
| Overall Wheelbase (engine & tender) | 46.12' | 48.58' |
| Axle Loading (Maximum Weight per Axle) | ||
| Weight on Drivers | 47000 lbs | 60500 lbs |
| Engine Weight | 75000 lbs | 95000 lbs |
| Tender Light Weight | 65000 lbs | 70000 lbs |
| Total Engine and Tender Weight | 140000 lbs | 165000 lbs |
| Tender Water Capacity | 4000 gals | 4500 gals |
| Tender Fuel Capacity (oil/coal) | 1500 gals | 1800 gals |
| Minimum weight per yard of rail on which locomotive could run | 39 lb rail | 50 lb rail |
| Geometry Relating to Tractive Effort | ||
| Driver Diameter | 63" | 63" |
| Boiler Pressure | 145 psi | 150 psi |
| Cylinders (dia x stroke) | 16" x 24" | 18" x 24" |
| Tractive Effort | 12020 lbs | 15737 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.91 | 3.84 |
| Heating Ability | ||
| Firebox Area | 100 sq. ft | 155 sq. ft |
| Grate Area | 16 sq. ft | 18 sq. ft |
| Evaporative Heating Surface | 1005 | 1305 |
| Superheating Surface | ||
| Combined Heating Surface | 1005 | 1305 |
| Evaporative Heating Surface/Cylinder Volume | 179.94 | 184.62 |
| Computations Relating to Power Output (More Information) | ||
| Robert LeMassena's Power Computation | 2320 | 2700 |
| Same as above plus superheater percentage | 2320 | 2700 |
| Same as above but substitute firebox area for grate area | 14500 | 23250 |
| Power L1 | 4103 | 4635 |
| Power MT | 384.92 | 337.80 |
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