Running under Chapman Timber oversight, this engine only operated out of Scapoose for 8 years. She then went to the Alton & Southern (in East St Louis, Ill.).
Davis's account pays special attention to the Baldwin "separable boiler" in a description that outdoes others in clarity. The rear part of the boiler had the firetubes common to all "Stephenson" boilers, although these were uncommonly short. The front half of the barrel had two bundles of tubes. In the back part of the front half (still with me?) rested a flue-gas feed water heater offering a total of 1,006 sq ft of surface to heat incoming tender water. A reheater in the smokebox (the 421 sq ft attributed to the "superheater" in the specs) was an intermediate point in the cycle where the exhausting steam from the HP cylinders was reheated before entering the LP cylinders.
Baldwin promoted this concept extensively for a few years, but almost all such Mallets were rebuilt with a standard boiler within a few years. Remarkably, this lone logger seems to have kept its oddly laid out boiler until it was scrapped.
| Specifications | |
|---|---|
| Class | |
| Locobase ID | 4059 |
| Railroad | Portland & Southwestern |
| Whyte | 2-6-6-2 |
| Road Numbers | 2 |
| Gauge | Std |
| Builder | Baldwin |
| Year | 1910 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase | 9' |
| Engine Wheelbase | 26.75' |
| Ratio of driving wheelbase to overall engine wheebase | 0.34 |
| Overall Wheelbase (engine & tender) | 42' |
| Axle Loading (Maximum Weight per Axle) | |
| Weight on Drivers | 202000 lbs |
| Engine Weight | 232000 lbs |
| Tender Light Weight | 100000 lbs |
| Total Engine and Tender Weight | 332000 lbs |
| Tender Water Capacity | 5000 gals |
| Tender Fuel Capacity (oil/coal) | 2000 gals |
| Minimum weight per yard of rail on which locomotive could run | 56.11 lb rail |
| Geometry Relating to Tractive Effort | |
| Driver Diameter | 51" |
| Boiler Pressure | 200 psi |
| Cylinders (dia x stroke) | 18.5" x 28" |
| Low Pressure Cylinders (dia x stroke) | 28" x 28" |
| Tractive Effort | 44472 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.54 |
| Heating Ability | |
| Firebox Area | 148 sq. ft |
| Grate Area | 41.80 sq. ft |
| Evaporative Heating Surface | 2904 |
| Superheating Surface | 421 |
| Combined Heating Surface | 3325 |
| Evaporative Heating Surface/Cylinder Volume | 333.36 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 8360 |
| Same as above plus superheater percentage | 9418.51 |
| Same as above but substitute firebox area for grate area | 33347.85 |
| Power L1 | 6332.32 |
| Power MT | 414.66 |
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