Central Mexicano / Interoceanico / Nacional de Mexico 2-8-2 Locomotives in Mexico


Class Details by Steve Llanso of Sweat House Media

Class 207 (Locobase 9631)

Data from Catalogue Descriptive of Simple and Compound Locomotives built by Brooks Locomotive Works, Dunkirk, NY (Buffalo, NY: Matthew-Northrup Company, 1899).

Builder info from B.Rumary, 25 Kingscombe, Gurney Slade, Radstock, BA3 4TH, ENGLAND and Jeremy Lambert as supplied by Allen Stanley in March 2004.

Works numbers were 2826-2835.

Obviously based on the Consolidations described in Locobase 9627, this single "Consolidation Freight, Double Ender" had an "Improved Belpaire" boiler with quite a few boiler tubes. Possibly built to spread the weight over one more axle, the single design was not a success, apparently, as it was soon rebuilt as a 2-8-0. Thus, it should not be seen as an early Mikado, examples of which were then in production for Japan (Locobase


Class 50 (Locobase 11709)

Data from Baldwin Locomotive Works Specification for Engines, 1890, as digitized by the DeGolyer Library of Southern Methodist University Volume 16, p. 122. Works numbers were 11284-11285 in October 1890; 11324-11325, 11348, 11357, 11371-11372, 11393, 11407 in November.

This class was delivered in a double-ender design with an outside frame, a construction used in some 400 locomotives to allow for wider grates in narrow gauges. The wheel arrangement previewed the Mikado layout, but in fact featured a trailing axle intended to guide the backing locomotive in the same way as the leading truck.

The innovation didn't last - the trailing trucks were removed by the end of 1891; see Locobase 11900 for the resulting class G-012 Consolidations.


Class KR-1 (Locobase 1378)

Data from NdeM 1946 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange and DeGolyer, Volume 65, pp. 410+. Works numbers were 54635-54639 in March 1921.

Drury's (1993) comment on these (very) light standard-gauge Mikados is borne out by the photographs. They were, he said, "curiously anachronistic, with inside-bearing trailing trucks, odd-looking domes, and capped stacks." Baldwin's specification includes a tonnage rating of 775 short tons (705 metric tons) up a 1 1/2% grade. The Southern gear was later replaced by Baker valve gear.

The last was retired in 1963.


Class KR-2 (Locobase 1379)

Data from Railway Age (12 Nov 1921) and DeGolyer Library, Volume. 65, pp. 410+ and Volume 74, pp. 422+. Baldwin works numbers were 54957-54960, 54974-54977, 54995-54999 in August 1921; 55001-55010 in September 1921.

Part of a variegated stud of locomotives ordered from Baldwin in 1921; some were built by Alco-Brooks. These medium-weight oil-burning Mikes, the MR-6 Pacifics, and the PR-7 4-8-0 all had the same boiler (tubes, grate area, firebox identical). The Baldwin specs state that the KR-1s were to haul 775 short tons (704 metric tons) up a straight grade of 1 1/2% where frictional resistance was not to exceed 8 lb/ton (3.3 kg/metric ton).

All had Ragonnet power reverse. 906-910 had Southern valve gear actuating 12" (305 mm) piston valves; 911-918, 926-932, and 941-950 were delivered with Young gear working 14" (356 mm) piston valves, and 933-940 used Baker radial valve gear for its 14" piston valves.

See Volume 74, pp. 425 for the beginning of a long letter of 24 May 1932 that describes drafting experiments. The writer noted that experiments on the NdeM had led to the adoption of "large exhaust tips, the substitution of a stack extension for the petticoat pipe, and a substantial increase in the stack diameter." The changes resulted in "low back pressure and a comparative high smoke box draft."

This class ran until 1953-1963.

Principal Dimensions by Steve Llanso of Middle Run Media

Class20750KR-1KR-2
Locobase ID9631 11709 1378 1379
RailroadCentral Mexicano (NdeM)Interoceanico (NdeM)Nacional de Mexico (NdeM)Nacional de Mexico (NdeM)
CountryMexicoMexicoMexicoMexico
Whyte2-8-22-8-22-8-22-8-2
Number in Class110540
Road Numbers20750-59800-804/ 906-910 / 2101-2105906-918, 926-950/2101-2145
GaugeStd3'StdStd
Number Built110540
BuilderBrooksBurnham, Parry, Williams & CoBaldwinseveral
Year1897189019211921
Valve GearStephensonStephensonSouthernvarious
Locomotive Length and Weight
Driver Wheelbase (ft / m)13 / 3.9610.25 / 3.1213.08 / 3.9915 / 4.57
Engine Wheelbase (ft / m)28.17 / 8.5924.83 / 7.5727.08 / 8.2533.59 / 10.24
Ratio of driving wheelbase to overall engine wheelbase 0.46 0.41 0.48 0.45
Overall Wheelbase (engine & tender) (ft / m)52.17 / 15.9046.23 / 14.0959.71 / 18.2066.80 / 20.36
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)145,200 / 65,86268,000 / 30,844144,000 / 65,317210,000 / 95,255
Engine Weight (lbs / kg)193,450 / 87,74874,000 / 33,566180,000 / 81,647270,000 / 122,470
Tender Loaded Weight (lbs / kg)90,000 / 40,823152,233 / 69,052169,000 / 76,657
Total Engine and Tender Weight (lbs / kg)283,450 / 128,571332,233 / 150,699439,000 / 199,127
Tender Water Capacity (gals / ML)4500 / 17.052500 / 9.478000 / 30.308500 / 32.20
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 8.50 / 83000 / 11,3553500 / 13,248
Minimum weight of rail (calculated) (lb/yd / kg/m)61 / 30.5028 / 1460 / 3088 / 44
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)49 / 124537 / 94048 / 121957 / 1448
Boiler Pressure (psi / kPa)180 / 12.40130 / 9180 / 12.40190 / 13.10
High Pressure Cylinders (dia x stroke) (in / mm)21" x 26" / 533x66016" x 20" / 406x50820" x 28" / 508x71125" x 30" / 635x762
Tractive Effort (lbs / kg)35,802 / 16239.5315,291 / 6935.8935,700 / 16193.2753,125 / 24097.12
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.06 4.45 4.03 3.95
Heating Ability
Tubes (number - dia) (in / mm)412 - 2" / 51134 - 2.25" / 57199 - 2" / 51231 - 2" / 51
Flues (number - dia) (in / mm)28 - 5.375" / 13736 - 5.375" / 137
Flue/Tube length (ft / m)12.12 / 3.6914.36 / 4.3816.25 / 4.9519.25 / 5.87
Firebox Area (sq ft / m2)218 / 20.2667.49 / 6.27154 / 14.31228 / 21.18
Grate Area (sq ft / m2)31.45 / 2.9216.25 / 1.5141.30 / 3.8466.60 / 6.19
Evaporative Heating Surface (sq ft / m2)2803 / 260.501056 / 98.142475 / 230.023517 / 326.86
Superheating Surface (sq ft / m2)530 / 49.26828 / 76.95
Combined Heating Surface (sq ft / m2)2803 / 260.501056 / 98.143005 / 279.284345 / 403.81
Evaporative Heating Surface/Cylinder Volume269.00227.10243.12206.40
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation56612113743412,654
Same as above plus superheater percentage56612113877215,058
Same as above but substitute firebox area for grate area39,240877432,71051,551
Power L15492240211,33812,827
Power MT333.55311.50694.33538.64

  • 2206 (Harold Van Horn Photo, YesterYearDepot)
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