Arcata & Mad River 2-4-2 "Columbian" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class Hoopa (Locobase 12463)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Vol 23, p. 182. Works number was 18564 in January 1901.

The A & MR RR served the logging industry by delivering the product to Humboldt Bay. Built as plank road in the 1850s, the line later adopted this odd gauge, roughly halfway between the 3' and standard gauge widths usually used in North America.

Specifications by Steve Llanso of Sweat House Media
Locobase ID12463
RailroadArcata & Mad River
Number in Class1
Road Numbers5
Gauge3' 9.25
Number Built1
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase 6.25'
Engine Wheelbase12.33'
Ratio of driving wheelbase to overall engine wheebase 0.51
Overall Wheelbase (engine & tender)
Axle Loading (Maximum Weight per Axle)
Weight on Drivers26000 lbs
Engine Weight32000 lbs
Tender Light Weight20000 lbs
Total Engine and Tender Weight52000 lbs
Tender Water Capacity800 gals
Tender Fuel Capacity (oil/coal)
Minimum weight of rail (calculated)22 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter37"
Boiler Pressure160 psi
Cylinders (dia x stroke)10" x 16"
Tractive Effort5881 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.42
Heating Ability
Firebox Area43 sq. ft
Grate Area 8.19 sq. ft
Evaporative Heating Surface308 sq. ft
Superheating Surface
Combined Heating Surface308 sq. ft
Evaporative Heating Surface/Cylinder Volume211.77
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1310
Same as above plus superheater percentage1310
Same as above but substitute firebox area for grate area6880
Power L13548
Power MT601.69

If you have any railroad data such as diagram books, rail station plans or anything else that you would be willing to share, please contact us.