United Verde & Pacific 2-6-0 "Mogul" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 1 (Locobase 12110)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Vol 19, p. 117. Works numbers were 14026-14027 in June 1894. See also Allen A Dutton, Arizona Then & Now (Big Earth Publishing, 2002).

The UV & P served copper mines in the Jerome, Arizona region that owned the reputation in 1914 of being one of the best copper mines in the world. Dutton (p. 58) reports that the 28-mile line between Jerome and the Santa Fe at Prescott had the reputation for being the crookedest line in the world and that "[p]eople joked that passengers in a rear car could look across curves and talk to the engineer." The railroad also brought out silver and gold.

To open the line, the railway bought these two Vauclain compounds. They had two 8" piston valves and were required to traverse curves of 100-ft (30-m) radius (40-45 degrees of curvature) and scale grades of up to 3%

2 had a short career before being wrecked in 1897. 1 remained on the line until it was closed in 1920.

Class 3 (Locobase 12181)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Vol 20, p. 88. Works number was 14676 in January 1896.

The first two locomotives purchased for the UV & P were the Vaulclain-compound Moguls described in Locobase 12110. More than a year later, the next Mogul arrived as a simple-expansion engine with more and longer tubes of the same large diameter. A diagram shows the desired weight by axle. Front to back the specification read 10,000 lb; 21,000 lb; 24,000 lb; and 23,000 lb.

Alas, the 3 had a short career on the UV & P before she was wrecked in March 1905.

Class 5 (Locobase 12182)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Vol 27,. p. 32. Works numbers were 24183 in May 1904., 25601, 25624 in May 1905, 30139 in February 1907, 31785 in September, and 32328 in December.

This sextet (and possibly #4 --- works 15536 of October 1897) were slight revisions of the #3 shown in Locobase 12181. The 2 and 3 were replacements for two wrecked predecessors.

The builder retain the same number of tubes but shortened them by 6", which also cut down the wheelbase by a foot, and increased driver diameter by 2". A possible reason for the bobtailing may have lain in the curve restriction set out in the specification - curves could bend at 40-45 degrees of curvature and grades could pitch to 3%. The taller drivers may have been prompted by the operation of mixed trains that needed go a bit quicker perhaps.

All three apparently served the UV & P until it was abandoned in 1920. 8 was sold to Central Lumber Company in February 1923.

Specifications by Steve Llanso of Sweat House Media
Locobase ID12,110 12,181 12,182
RailroadUnited Verde & PacificUnited Verde & PacificUnited Verde & Pacific
Number in Class216
Road Numbers1-235-8, 2-3
Number Built216
BuilderBurnham, Williams & CoBurnham, Williams & CoBurnham, Williams & Co
Valve GearStephensonStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft)998
Engine Wheelbase (ft)15.5816.3316.33
Ratio of driving wheelbase to overall engine wheebase 0.58 0.55 0.49
Overall Wheelbase (engine & tender) (ft)15.5841.1741.17
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)70,00070,000
Engine Weight (lbs)80,00079,400
Tender Loaded Weight (lbs)76,000
Total Engine and Tender Weight (lbs)155,400
Tender Water Capacity (gals)200030003800
Tender Fuel Capacity (oil/coal) (gals/tons)1200
Minimum weight of rail (calculated) (lb/yd)3939
Geometry Relating to Tractive Effort
Driver Diameter (in)414143
Boiler Pressure (psi)180160160
High Pressure Cylinders (dia x stroke) (in)10" x 20"17" x 20"17" x 20"
Low Pressure Cylinders (dia x stroke) (in)17" x 20"
Tractive Effort (lbs)11,09019,17318,281
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.65 3.83
Heating Ability
Firebox Area (sq ft)5977.9085
Grate Area (sq ft)15.2016.7516.75
Evaporative Heating Surface (sq ft)93310861056
Superheating Surface (sq ft)
Combined Heating Surface (sq ft)93310861056
Evaporative Heating Surface/Cylinder Volume513.19206.69200.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation273626802680
Same as above plus superheater percentage273626802680
Same as above but substitute firebox area for grate area10,62012,46413,600
Power L1287530703232
Power MT290.07305.37