Minera de Petioles 2-6-2 Locomotives in Mexico

Class Details by Steve Llanso of Sweat House Media

Class Bermejillo (Locobase 12449)

Data from Baldwin Locomotive Works Specification for Engines, 1890, as digitized by the DeGolyer Library of Southern Methodist University Vol 23, p.138 Works numbers were 18355 in October 1900, 21721 in February 1903, and 37796 in August 1911.

Many small mining roads built to a certain standard and didn't substantially upgrade that level - traffic levels and revenue didn't call for it. So it wasn't uncommon for the first locomotive to arrive in year 1 (in the case of the Bermejillo, 1900), the second a few years later (San Pedro in 1903), and a third built to the same specs even later (San Juan in 1911). Each was expected to negotiate curves of 41-metre radius (> 20 deg) and manage a ruling grade of 1 3/4% (92 ft to the mile).

Principal Dimensions by Steve Llanso of Middle Run Media

Locobase ID12449
RailroadMinera de Petioles
Number in Class3
Road Numbers
Number Built3
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 7.25 / 2.21
Engine Wheelbase (ft / m)19.58 / 5.97
Ratio of driving wheelbase to overall engine wheelbase 0.37
Overall Wheelbase (engine & tender) (ft / m)19.58 / 5.97
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)35,000 / 15,876
Engine Weight (lbs / kg)47,000 / 21,319
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)47,000
Tender Water Capacity (gals / ML)1000 / 3.79
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)19 / 9.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)35 / 889
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)12" x 16" / 305x406
Tractive Effort (lbs / kg)8953 / 4061.02
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.91
Heating Ability
Tubes (number - dia) (in / mm)72 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)11.08 / 3.38
Firebox Area (sq ft / m2)41.80 / 3.88
Grate Area (sq ft / m2)9 / 0.84
Evaporative Heating Surface (sq ft / m2)456 / 42.38
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)456 / 42.38
Evaporative Heating Surface/Cylinder Volume218.18
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1440
Same as above plus superheater percentage1440
Same as above but substitute firebox area for grate area6688
Power L12970
Power MT561.23

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