Although only 2 in number and home-built, these Atlantics followed the lines of the classic express locomotive in many respects. Although the boiler was relatively small in relation to the cylinders, the firebox ratios stood almost squarely in the middle of the more than 100 designs examined in this comparison. And a look at the profile shows large-diameter trailing wheels (51") under the firebox.
Unfortunately, says Drury (1993) "They turned out to be rear-heavy and unstable, and their 28,000 lb of tractive effort was no more than that of the considerably lighter D-9 Ten-Wheelers that preceded them."
Delivered as saturated-steam engines in 1906, they were superheated in 1917, at which time they were fitted with 14" piston valves and Southern valve gear. Thus equipped, they served the T & P for another decade.
| Specifications | |
|---|---|
| Class | E-1-s |
| Locobase ID | 8494 |
| Railroad | Texas & Pacific (T & P) |
| Whyte | 4-4-2 |
| Road Numbers | 339-340 |
| Gauge | Std |
| Builder | Texas & Pacific |
| Year | 1906 |
| Valve Gear | Southern |
| Locomotive Length and Weight | |
| Driver Wheelbase | 7' |
| Engine Wheelbase | 27.58' |
| Ratio of driving wheelbase to overall engine wheebase | 0.25 |
| Overall Wheelbase (engine & tender) | 56.87' |
| Axle Loading (Maximum Weight per Axle) | |
| Weight on Drivers | 123900 lbs |
| Engine Weight | 213986 lbs |
| Tender Light Weight | 114879 lbs |
| Total Engine and Tender Weight | 328865 lbs |
| Tender Water Capacity | 6500 gals |
| Tender Fuel Capacity (oil/coal) | 3000 gals |
| Minimum weight per yard of rail on which locomotive could run | 103 lb rail |
| Geometry Relating to Tractive Effort | |
| Driver Diameter | 75" |
| Boiler Pressure | 185 psi |
| Cylinders (dia x stroke) | 22" x 28" |
| Tractive Effort | 28414 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.36 |
| Heating Ability | |
| Firebox Area | 180 sq. ft |
| Grate Area | 45 sq. ft |
| Evaporative Heating Surface | 2470 |
| Superheating Surface | 525 |
| Combined Heating Surface | 2995 |
| Evaporative Heating Surface/Cylinder Volume | 200.50 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 8325 |
| Same as above plus superheater percentage | 9990 |
| Same as above but substitute firebox area for grate area | 39960 |
| Power L1 | 15196 |
| Power MT | 540.78 |
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