Monte Alto y Tlalnepantla 2-2-0 Locomotives in Mexico

Class Details by Steve Llanso of Sweat House Media

Class 6 (Locobase 15334)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 74, p. 395+. Works numbers were 57606-57607 in January 1924.

These steam trams clearly were based on an inspection engine design built in 1908 for the Guiler-Gordon Engineering company, which operated in Cuba (see Locobase 13280). The six-inch (152 mm) difference in gauge allowed the MA y T to use a slightly bigger grate, although its use of oil as a fuel made the firebox heating surface area more important. The two engines rode on 16 lb/yard (8 kg/metre) rail. As far as Locobase can determine, the power unit was independent of the tram car, to which it was coupled using a Baldwin CUH bull-nose link-and-pin coupler.

The line ran from Tlalnepantla, northeast of Mexico City proper, down to Azcapotzalco. Not long after the steam tram locomotives arrived, the tramway adopted gasoline power.

Principal Dimensions by Steve Llanso of Middle Run Media

Locobase ID15334
RailroadMonte Alto y Tlalnepantla
Number in Class2
Road Numbers6-7
Number Built2
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)
Engine Wheelbase (ft / m)6 / 1.83
Ratio of driving wheelbase to overall engine wheelbase
Overall Wheelbase (engine & tender) (ft / m)6 / 1.83
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)10,000 / 4536
Engine Weight (lbs / kg)17,500 / 7938
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)17,500
Tender Water Capacity (gals / ML)300 / 1.14
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)75 / 284
Minimum weight of rail (calculated) (lb/yd / kg/m)17 / 8.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)24 / 610
Boiler Pressure (psi / kPa)150 / 10.30
High Pressure Cylinders (dia x stroke) (in / mm)6.5" x 10" / 165x254
Tractive Effort (lbs / kg)2245 / 1018.32
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.45
Heating Ability
Tubes (number - dia) (in / mm)37 - 1.5" / 38
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)6 / 1.83
Firebox Area (sq ft / m2)16 / 1.49
Grate Area (sq ft / m2) 3.85 / 0.36
Evaporative Heating Surface (sq ft / m2)102 / 9.48
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)102 / 9.48
Evaporative Heating Surface/Cylinder Volume268.42
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation578
Same as above plus superheater percentage578
Same as above but substitute firebox area for grate area2400
Power L12874
Power MT633.61

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