The 20-mile (32 km) Yellowstone Park Railroad was built by Samuel Hauser to exploit the Clark's Fork coal reserves. It was constructed in 1905-1906 on little or no ballast and used 60 lb/yard (30 kg/metre) relay (already used) rail. Its "professional although not always ethical promoter" Frank Hall did complete the short line that included Bridger, Belfry and Bear Creek before waging a war against the bond holders that led them buying him out in 1909 and renaming the railroad.
Even after the change of management, the MW&S was scored for its "bad service, the poor condition of its line, and its abysmal maintenance program." In a 1912 complaint, the track bed was characterized as being "in fierce condition." Only the employment of William Harry Bunney as general manager in 1918 led to substantial improvement.
It was at that time that the road ordered this medium-sized Consolidation from Eddystone. The specs cited 56 lb/yard (28 kg) rail, 4% and 5% grades, and 14 degree curves (radii of 269 feet/82 metres) as challenges to the locomotive. Superheated steam was admitted to the cylinders through relatively large 12" (305 mm) piston valves.
A sister joined the 10 six years later. A significant change concerned ergonomics. The MW&S found in practice that the only way for the engineer to see out the window when switching was to bend over. The 12 was fitted with the #20's cab design (see Locobase 15304 for the 20), which allowed the engineer to remain standard while looking out the window.
Nevertheless, the railroad's enduring value to the area as the MW&S kept it in business for nearly 50 years. As Jon Axline puts it, the railroad "had a profound impact on how south central Montana developed."
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Montana, Wyoming & Southern|
|Number in Class||2|
|Road Numbers||10, 12|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.65|
|Overall Wheelbase (engine & tender)||57.50'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||154000 lbs|
|Engine Weight||175000 lbs|
|Tender Light Weight||141000 lbs|
|Total Engine and Tender Weight||316000 lbs|
|Tender Water Capacity||7000 gals|
|Tender Fuel Capacity (oil/coal)||12 tons|
|Minimum weight of rail (calculated)||64 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||190 psi|
|Cylinders (dia x stroke)||21" x 28"|
|Tractive Effort||36930 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.17|
|Firebox Area||137 sq. ft|
|Grate Area||40 sq. ft|
|Evaporative Heating Surface||1837 sq. ft|
|Superheating Surface||366 sq. ft|
|Combined Heating Surface||2203 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||163.66|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||7600|
|Same as above plus superheater percentage||8892|
|Same as above but substitute firebox area for grate area||30455|