Sonora 4-6-0 Locomotives in Mexico

Class Details by Steve Llanso of Sweat House Media

Class 18 (Locobase 12439)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 23, p 98. Works number was 18104 in September 1900.

Locobase loves turning up new combinations of familiar locomotives. Here's a mixed-traffic camelback for a Mexican railroad. The Southern Pacific, not known for double cabs, procured one for the Sonora.

It didn't last long in that configuration. The Espee took back the engine in 1905 and rebuilt in May 1906. It was scrapped in April 1928.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID12439
Number in Class1
Road Numbers18
Number Built1
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.50 / 3.81
Engine Wheelbase (ft / m)23.33 / 7.11
Ratio of driving wheelbase to overall engine wheelbase 0.54
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)105,000 / 47,627
Engine Weight (lbs / kg)138,000 / 62,596
Tender Loaded Weight (lbs / kg)75,000 / 34,019
Total Engine and Tender Weight (lbs / kg)213,000 / 96,615
Tender Water Capacity (gals / ML)4000 / 15.15
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)58 / 29
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)69 / 1753
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)19" x 26" / 483x660
Tractive Effort (lbs / kg)18,500 / 8391.47
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.68
Heating Ability
Tubes (number - dia) (in / mm)224 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)14 / 4.27
Firebox Area (sq ft / m2)176 / 16.36
Grate Area (sq ft / m2)76 / 7.06
Evaporative Heating Surface (sq ft / m2)1803 / 167.57
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1803 / 167.57
Evaporative Heating Surface/Cylinder Volume211.37
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation12,160
Same as above plus superheater percentage12,160
Same as above but substitute firebox area for grate area28,160
Power L15787
Power MT364.52

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Wes Barris