Minera de Naica 2-8-2 Locomotives in Mexico


Class Details by Steve Llanso of Sweat House Media

Class 3 (Locobase 13000)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Vol 27, p.54. Works numbers were 24202 in April 1904 and 24331 in May.

Not long after the mines opened, these two tiny outside-frame Mikados reported for duty to serve a mining operation that extracted both silver and lead. Photographs illustrate the total obscuration of the tiny drivers inside the heavy frames and broad-mouthed spark-arresting stack.

The 26-mile long line was also called the Conchos Railway after the junction that met the Mexican Central. The Peñoles would buy the line in 1920 and continue in service until 1946.

The mines would later gain fame for the gigantic crystal formations discovered in the caves nearby.


Class 5 (Locobase 13001)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Vol 29, p.103. Works number was 28952 in September 1906.

To bolster the motive-power roster, this outside-frame Mikado featured more power and a bigger boiler than each of the two earlier 2-8-2s (Locobase 13000). Specifications called for this diminuitive Mikado to haul 200 tons up a 1 1/2% grade .

Principal Dimensions by Steve Llanso of Middle Run Media

Class35
Locobase ID13000 13001
RailroadMinera de Naica (Conchos)Minera de Naica (Conchos)
CountryMexicoMexico
Whyte2-8-22-8-2
Number in Class21
Road Numbers3-45
Gauge2'6"2'6"
Number Built21
BuilderBurnham, Williams & CoBurnham, Williams & Co
Year19041906
Valve GearStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 7.92 / 2.41 8.50 / 2.59
Engine Wheelbase (ft / m)18.83 / 5.7420.75 / 6.32
Ratio of driving wheelbase to overall engine wheelbase 0.42 0.41
Overall Wheelbase (engine & tender) (ft / m)36.12 / 11.0141.50 / 12.65
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)27,000 / 12,24743,500 / 19,731
Engine Weight (lbs / kg)37,500 / 17,01058,400 / 26,490
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)1200 / 4.552500 / 9.47
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)11 / 5.5018 / 9
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)28 / 71130 / 762
Boiler Pressure (psi / kPa)150 / 10.30170 / 11.70
High Pressure Cylinders (dia x stroke) (in / mm)10" x 14" / 254x35612" x 18" / 305x457
Tractive Effort (lbs / kg)6375 / 2891.6512,485 / 5663.11
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.24 3.48
Heating Ability
Tubes (number - dia) (in / mm)53 - 2" / 51105 - 1.75" / 44
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)10.79 / 3.2912 / 3.66
Firebox Area (sq ft / m2)41.50 / 3.8641 / 3.81
Grate Area (sq ft / m2) 9.80 / 0.9110.50 / 0.98
Evaporative Heating Surface (sq ft / m2)338 / 31.41615 / 57.16
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)338 / 31.41615 / 57.16
Evaporative Heating Surface/Cylinder Volume266.14260.59
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation14701785
Same as above plus superheater percentage14701785
Same as above but substitute firebox area for grate area62256970
Power L130072953
Power MT982.12598.64

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