This trio of Decapods sent built for the EP & SW in February, June, & July 1903 were the only engines of that wheel arrangement ever operated in the entire SP Lines systems. These were seriously drag-freight locomotives, although relatively small and possessing a tractive effort only as large as a small Mikado would exert a decade later. Still, they hung on for more than three decades, moving on to the SA & AP in the mid--1920s. Locobase 8681 shows the results of superheating this class.
Delivered to the El Paso & Southwestern as the Espee System's only Decapods (Locobase 8680), this trio was bought by the SA & AP in the 1920s. Locobase isn't sure when they were superheated. Whoever wrought the makeover, they effected a good trade-off between deleting small tubes and installing the larger superheater flues. For some reason, the engines gained 24 tons (!) in the upgrade, a more-than-usual 10% increase.
The modified engines lasted only about a decade longer before heading for scrap on 23 November 1936 (361), and 2 and 4 June 1937 for the other two.
| Specifications | ||
|---|---|---|
| Class | D-1 | D-1 - superheated |
| Locobase ID | 8680 | 8681 |
| Railroad | El Paso & Southwestern (SP) | San Antonio & Aransas Pass (SP) |
| Whyte | 2-10-0 | 2-10-0 |
| Road Numbers | 360-362 | 360-362 |
| Gauge | Std | Std |
| Builder | Burnham, Williams & Co | SA & AP |
| Year | 1903 | 1923 |
| Valve Gear | Stephenson | Stephenson |
| Locomotive Length and Weight | ||
| Driver Wheelbase | 19.33' | 19.33' |
| Engine Wheelbase | 27.67' | 27.67' |
| Ratio of driving wheelbase to overall engine wheebase | 0.70 | 0.70 |
| Overall Wheelbase (engine & tender) | 58.45' | 58.45' |
| Axle Loading (Maximum Weight per Axle) | 51270 lbs | |
| Weight on Drivers | 200000 lbs | 221360 lbs |
| Engine Weight | 220000 lbs | 248590 lbs |
| Tender Light Weight | 150000 lbs | 150000 lbs |
| Total Engine and Tender Weight | 370000 lbs | 398590 lbs |
| Tender Water Capacity | 7500 gals | 7500 gals |
| Tender Fuel Capacity (oil/coal) | 14 tons | 14 tons |
| Minimum weight per yard of rail on which locomotive could run | 67 lb rail | 74 lb rail |
| Geometry Relating to Tractive Effort | ||
| Driver Diameter | 51.50" | 51.50" |
| Boiler Pressure | 190 psi | 190 psi |
| Cylinders (dia x stroke) | 23" x 28" | 23" x 28" |
| Tractive Effort | 46449 lbs | 46449 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.31 | 4.77 |
| Heating Ability | ||
| Firebox Area | 211.50 sq. ft | 212.40 sq. ft |
| Grate Area | 68.90 sq. ft | 68.90 sq. ft |
| Evaporative Heating Surface | 3599 | 2490 |
| Superheating Surface | 611 | |
| Combined Heating Surface | 3599 | 3101 |
| Evaporative Heating Surface/Cylinder Volume | 267.30 | 184.93 |
| Computations Relating to Power Output (More Information) | ||
| Robert LeMassena's Power Computation | 13091 | 13091 |
| Same as above plus superheater percentage | 13091 | 15709 |
| Same as above but substitute firebox area for grate area | 40185 | 48427 |
| Power L1 | 5640 | 10963 |
| Power MT | 310.85 | 545.93 |
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