Coronado 2-8-0 "Consolidation" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 20 (Locobase 12669)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 25, p. 244. Works numbers were 21882 in March 1903, 24313 in June 1904, 26660 in October 1905, and 30726 in April 1907.

The Arizona Copper Company, headquartered in Clifton, oversaw a wide-ranging set of mines throughout Arizona and New Mexico. The ACC bought this quartet of skinny-rail Consolidations to operate on the A & NM's narrow-gauge Coronado Railroad, which served Metcalf. The design's grate and firebox were a bit small to serve the relatively big boiler; on the other hand, the small power dimensions meant that at the typically low speeds this railroad would allow, the engines probably encountered little trouble keeping up steam.

Of more immediate interest to Mr A T Thomson of Arizona Copper on 27 February 1904 (according to a letter in the specification book) was a desired revision in the truck design of the 22, then under order at Baldwin. 20 was delivered with a swinging truck, but the railroad changed it to a roller truck. (Noter: swinging link and roller were two different ways to center a 2-wheel truck when it was displaced during an entrance to a curve.)

"We had to make this alteration on the last engine," reported Thomson, "on account of our having considerable trouble and annoyance with the engine getting off the track and it appears the hindmost pair of drivers were always the first to get off." Locobase can't say for sure, but it seems likely 22 was delivered with a roller truck.

Phelps-Dodge bought the railroad in 1921 and closed it. 20 was sold to United States Potash as their #3, 22 and 25 remained with Phelps Docdge, and 23 was sold to Railway * Mining Supply Company.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID12669
Number in Class4
Road Numbers20, 22-23, 25
Number Built4
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)10.50 / 3.20
Engine Wheelbase (ft / m)17.75 / 5.41
Ratio of driving wheelbase to overall engine wheebase 0.59
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)100,000 / 45,359
Engine Weight (lbs / kg)111,000 / 50,349
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)42 / 21
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)40 / 1016
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)17" x 20" / 432x508
Tractive Effort (lbs / kg)22,109 / 10028.49
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.52
Heating Ability
Firebox Area (sq ft / m2)74.80 / 6.95
Grate Area (sq ft / m2)19.62 / 1.82
Evaporative Heating Surface (sq ft / m2)1647 / 153.07
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1647 / 153.07
Evaporative Heating Surface/Cylinder Volume313.47
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3532
Same as above plus superheater percentage3532
Same as above but substitute firebox area for grate area13,464
Power L14616
Power MT407.06

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