Nacional de Mexico 4-6-4 Locomotives in Mexico


Class Details by Steve Llanso of Sweat House Media

Class NR-1 (Locobase 11950)

Data from NdeM 1950 Locomotive Diagrams Standard Gauge supplied in December 2010 by Allen Stanley. See also the 10 July 2010 blog post at [] by Matfas Lozano Dfaz de León on La Burrita, the one NR-1 to have been preserved.

These Hudsons vied with the Maine Central D-class 4-6-4s described in Locobase 1044 for the title of lightest of the arrangement on a North American railroad. But they suited NdeM practice quite well.

Principal Dimensions by Steve Llanso of Sweat House Media
ClassNR-1
Locobase ID11950
RailroadNacional de Mexico (NdeM)
CountryMexico
Whyte4-6-4
Number in Class10
Road Numbers2700-2709
GaugeStd
Number Built10
BuilderAlco-Schenectady
Year1937
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13 / 3.96
Engine Wheelbase (ft / m)37.75 / 11.51
Ratio of driving wheelbase to overall engine wheebase 0.34
Overall Wheelbase (engine & tender) (ft / m)69.08 / 21.06
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)170,000 / 77,111
Engine Weight (lbs / kg)292,000 / 132,449
Tender Loaded Weight (lbs / kg)173,660 / 78,771
Total Engine and Tender Weight (lbs / kg)465,660 / 211,220
Tender Water Capacity (gals / ML)8500 / 32.20
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)4037 / 15,280
Minimum weight of rail (calculated) (lb/yd / kg/m)94 / 47
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)73 / 1854
Boiler Pressure (psi / kPa)250 / 17.20
High Pressure Cylinders (dia x stroke) (in / mm)22.5" x 28" / 572x711
Tractive Effort (lbs / kg)41,263 / 18716.60
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.12
Heating Ability
Tubes (number - dia) (in / mm)178 - 2" / 51
Flues (number - dia) (in / mm)43 - 5.375" / 137
Flue/Tube length (ft / m)17 / 5.18
Firebox Area (sq ft / m2)281 / 26.11
Grate Area (sq ft / m2)66.80 / 6.21
Evaporative Heating Surface (sq ft / m2)2947 / 273.88
Superheating Surface (sq ft / m2)850 / 79
Combined Heating Surface (sq ft / m2)3797 / 352.88
Evaporative Heating Surface/Cylinder Volume228.63
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation16,700
Same as above plus superheater percentage20,374
Same as above but substitute firebox area for grate area85,705
Power L128,321
Power MT1101.83

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