Butte, Anaconda & Pacific 2-8-0 "Consolidation" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 25 / F-12 (Locobase 8833)

Data from GN 1916 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

The B A & P was built by Marcus Daly in 1892 to move the copper from his Butte-area mines over 26 miles of 75-lb track to the big smelter at Anaconda. The quartet of Consolidations in this entry helped move that ore until 1913, when the Biggest Little Railroad in the World electrified.

Soon after their supercession, 26 & 27 were bought by the Great Northern, classed F-12 and renumbered. Light-footed, low-drivered, and quite powerful for their size, the pair served the GN into the 1940s.

Principal Dimensions by Steve Llanso of Sweat House Media
Class25 / F-12
Locobase ID8833
RailroadButte, Anaconda & Pacific
Number in Class4
Road Numbers25-28 / 1326-1327
Number Built4
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)14.50 / 4.42
Engine Wheelbase (ft / m)22.25 / 6.78
Ratio of driving wheelbase to overall engine wheebase 0.65
Overall Wheelbase (engine & tender) (ft / m)54.67 / 16.66
Axle Loading (Maximum Weight per Axle) (lbs / kg)41,750 / 18,938
Weight on Drivers (lbs / kg)167,000 / 75,750
Engine Weight (lbs / kg)186,000 / 84,368
Tender Loaded Weight (lbs / kg)122,000 / 55,338
Total Engine and Tender Weight (lbs / kg)308,000 / 139,706
Tender Water Capacity (gals / ML)6000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)12 / 10.90
Minimum weight of rail (calculated) (lb/yd / kg/m)70 / 35
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)52 / 1321
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)21" x 28" / 533x711
Tractive Effort (lbs / kg)40,368 / 18310.64
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.14
Heating Ability
Firebox Area (sq ft / m2)180 / 16.73
Grate Area (sq ft / m2)46 / 4.28
Evaporative Heating Surface (sq ft / m2)2579 / 239.68
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)2579 / 239.68
Evaporative Heating Surface/Cylinder Volume229.76
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9200
Same as above plus superheater percentage9200
Same as above but substitute firebox area for grate area36,000
Power L15372
Power MT283.67

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