Unidos de Yucatan 2-8-0 Locomotives in Mexico


Class Details by Steve Llanso of Sweat House Media

Class 18 (Locobase 14188)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 49, p. 103. Works numbers were 40168-40169 in July 1913.

These wood-burning Consolidations served the Yucatan for more than 40 years. Like many rural narrow-gauge lines, the U de Y was lightly built with 35 lb/yard (17.5 kg/metre) rail. Moreover, said the specs, the builder was to "[p]rovide sufficient space between flues on account of bad water." Strength of the unit was a concern too: "The top row of flues should not be too close to corner of flue sheet." No measurements accompany this caution.

The 19 was retired in 1960 while the 20 was sold in 1963 to Unidos del Sureste, which renumbered it 280.

Principal Dimensions by Steve Llanso of Middle Run Media
Class18
Locobase ID14188
RailroadUnidos de Yucatan
CountryMexico
Whyte2-8-0
Number in Class2
Road Numbers18-19
Gauge3'
Number Built2
BuilderBaldwin
Year1913
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)10.58 / 3.22
Engine Wheelbase (ft / m)18.08 / 5.51
Ratio of driving wheelbase to overall engine wheelbase 0.59
Overall Wheelbase (engine & tender) (ft / m)44.87 / 13.68
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)80,000 / 36,287
Engine Weight (lbs / kg)90,000 / 40,823
Tender Loaded Weight (lbs / kg)60,000 / 27,216
Total Engine and Tender Weight (lbs / kg)150,000 / 68,039
Tender Water Capacity (gals / ML)3000 / 11.36
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)33 / 16.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)38 / 965
Boiler Pressure (psi / kPa)180 / 1240
High Pressure Cylinders (dia x stroke) (in / mm)16" x 20" / 406x508
Tractive Effort (lbs / kg)20,615 / 9350.82
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.88
Heating Ability
Tubes (number - dia) (in / mm)136 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)14.98 / 4.57
Firebox Area (sq ft / m2)62 / 5.76
Grate Area (sq ft / m2)16 / 1.49
Evaporative Heating Surface (sq ft / m2)1123 / 104.33
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1123 / 104.33
Evaporative Heating Surface/Cylinder Volume241.51
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2880
Same as above plus superheater percentage2880
Same as above but substitute firebox area for grate area11,160
Power L13513
Power MT387.24

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