Butte, Anaconda & Pacific 4-10-0 Locomotives

Class Details by Steve Llanso of Sweat House Media

Class unknown (Locobase 11467)

Data from "Locomotive Building," The Railroad Gazette, Vol XXXVIII, No 24 (June 1905), p 205. See also the pamphlet that describes the BA & P's big push toward electrification among other such projects "Progress Made in Electrification of Railroads and the Economies Effected Thereby", Presented by the BLE and the BLFE, quoting among others, Railway Age articles from 1914, archived at http://milwaukeeroadarchives.com/Electrification/1915%2001%2018%20Progress%20Made%20in%20the%20Electrification%20of%20Railroads%20and%20Economies%20Effected%20Thereof.pdf.

The RAarticle of 25 December 1914, p. 1194, gives us an insight into how the Mastodons were used in order to contrast them to the greater power of the electrics:

"On October 10 a double-unit electric locomotive was put in the day freight service on the main line between East Anaconda and Rocker, a distance of 20.1 miles. The steam locomotive replaced in this instance was of the Mastodon type ... The standard train hauled on the trip west was 50 to 55 loaded ore cars weighing approximately 3,500 to 4,000 tons gross and the average running time of such trains where no stops were made was about l 1/2 hours, corresponding to an average speed of approximately 13.4 miles per hour."

How did the electrics compare?

"In the beginning the electric locomotive took only the standard train, but made the trip without stop in about one hour, corresponding to an average speed of 20 miles per hour. The ruling gradient on the westward trip is 0.3 per cent and about half the distance is down grade. On the 0.3 per cent grade with a 55-car train, the steam locomotive made about 7 miles per hour. The electric locomotives with similar train now make about 16 miles per hour on the same grade."

Note too: "The weight of the trains hauled by the electric locomotives on this run has been gradually increased up to 65 loaded ore cars averaging about 71 tons each, making the gross weight trailing about 4,620 tons. Adding 160 tons for the weight of the double-unit electric locomotives and 20 tons for the caboose makes a gross train weight of approximately 4,800 tons."

How about elsewhere on the BA& P?:

"The service on the Missoula Gulch line running between Rocker and Butte Hill yards was taken over for electrical operation on October 20. This line is 4.5 miles in length and the ruling gradient 2.5 per cent. The steam locomotives used on this line were of the Mastodon type ...Two complete crews had been required to handle this service during steam operation, averaging six trips per day each. A single crew with a double-unit electric locomotive has been doing this work successfully. Thirty-five to 45 loaded ore cars are taken down from Butte Hill yard to Rocker, and about an equal number of empties taken up. In addition to the empties, large quantities of timber and supplies for the mines are delivered over this line."

Specifications by Steve Llanso of Sweat House Media
Locobase ID11467
RailroadButte, Anaconda & Pacific
Road Numbers
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase
Engine Wheelbase
Ratio of driving wheelbase to overall engine wheebase
Overall Wheelbase (engine & tender)
Axle Loading (Maximum Weight per Axle)
Weight on Drivers173480 lbs
Engine Weight212740 lbs
Tender Light Weight112000 lbs
Total Engine and Tender Weight324740 lbs
Tender Water Capacity5500 gals
Tender Fuel Capacity (oil/coal)10 tons
Minimum weight of rail (calculated)58 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter56"
Boiler Pressure210 psi
High Pressure Cylinders (dia x stroke)23" x 32"
Low Pressure Cylinders (dia x stroke)34" x 32" (1)
Tractive Effort37018 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.69
Heating Ability
Firebox Area
Grate Area34.75 sq. ft
Evaporative Heating Surface3380 sq. ft
Superheating Surface
Combined Heating Surface3380 sq. ft
Evaporative Heating Surface/Cylinder Volume439.30
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation7298
Same as above plus superheater percentage7298
Same as above but substitute firebox area for grate area0
Power L10
Power MT0

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