Mexican Railway 2-8-0 Locomotives in Mexico


Class Details by Steve Llanso of Sweat House Media

Class 71 (Locobase 6740)

Data from MexRy 1939 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

This relatively powerful set of Consolidations -- RI works #3087-3089 -- actually preceded the Alcos and Baldwins that were supplied over the next decade. They must have originally used Stephenson link valve gear and been retrofitted with Baker radial gear later. 72 differed from its two sisters at the time of the 1939 book in having 21"-diameter cylinders.


Class G-1 (Locobase 6737)

Data from MexRy 1939 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 10, p. 238 and Volume 11, p. 213. Works numbers were 5769-5770 in August 1881; 6638, 6642-6643 in March 1883; 6746, 6748 in May, and 6987 in September.

The date given in the diagram book for this class's arrival on the MR (1875) is contradicted by the work numbers. The Baldwin specs show a boiler with 198 tubes, each measuring just shy of 11 feet (3.34 m).

Each engine originally bore a name; taken all together, the list provides a glance at what seemed salient at the time: Guadalupe 1, Tenochtitlan, Texmelucan 54, Zacatlan 55, Zacapoaxtla 56, Palenque 57, Uxmal 58, Mitla, and Usumacinta 60. They were later renumbered 61- 62, 64-65, and 67-70.

Locobase groups this set under one entry because Connelly's list shows all but 69 (see Locobase 6738) in the G-1 group.

As with most MR locomotives, the class enjoyed a long career.


Class G-3 (Locobase 6742)

Data from MexRy 1939 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 31, pp. 141,142. Works numbers were 16473-16474 in January 1899; 24209, 24218 in May 1904; 24720-24721, 24724, 24734 in September, 30502; 30590-30591 in April 1907; 31634, 31638 in August 1907, 32345, 32480, 32481 in December 1907; and 32546, 32563 in January 1908.

The most numerous class of Consolidations on the Mexican Railway, this design was procured over an eight-year period. For some reason, 91's firebox was 2" shorter, which reduced direct heating surface to 198.7 sq ft (18.45 sq m).

The last two were delivered with the Allfree-Hubbell valve gear; see Locobase 7820 for a description of this double-walled system. In these specs, a separate paragraph gives the details on who is to supply or manufacture what:

James B Allfree, then a member of the the Locomotive Appliance Corporation's Board of Directors (which was headed up by Ira C Hubbell), was the inventor and supplied "free ...and completed finished"License plates on cylinder, main steam valves, main steam valve yokes, compression valves, compression valve stems. Compression valve operating arms."

Allfree also supplied the patterns for Baldwin to cast and machine the "cylinders, cylinder heads, steam chest balance plates." Baldwin would use its own patterns to make the cylinder oil cups, compression valve bushing and cylinder head and steam chest casing. the main steam valve glands were to be made in Eddystone and not by US Packing Company.

After further instructions, the specs state [in CAPITAL LETTERS not reproduced here]: "Notify J. B. Allfree, so he can come here to supervise placing of valves, etc."

By 1939, fire (93, 96, 100, 104, 105) had been refitted with Baker radial valve gear.


Class G-3 / G-24 (Locobase 13639)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 27, pp. 47 and 122. Works numbers were 24209, 24218 in May 1904; 24720-24721, 24724, 24736 in September.

This sextet of Consolidations had Belpaire fireboxes. Their 4-6-0 stablemates are shown in Locobase 13640.


Class GR-27 (Locobase 3236)

Data from "New Motive Power for Railways of Mexico", Railway Age, Volume 71, No 20 (12 November 1921), pp. 937-939; and DeGolyer Library, Vol 65, pp. 390+. Works numbers were 54845-54855 in June 1921.

The first eleven of these oil-burning Consolidations came in 1921 to work the Vera Cruz-Mexico City mainline freights, which RA noted covered 264 miles and "abounds in curves and grades." RA singled out a tunnel with a curve of 17 /12 deg radius. Maximum grade for this line was 4 1/2% (ca. 225 ft in the mile). RA also noted how quickly this order, taken on 25 May 1921, was filled: the last of 11 engines was shipped on 1 July.

The superheated steam was supplied to the cylinders through relatively capacious 14" (356 mm) piston valves.

Locobase note: The specs are identical to those for a pair of Consolidations bought by the Maryland & Pennsylvania in 1914 (see Locobase 6025). Seems to be a clear case of an order filled from a stock design, although RA says nothing about it.


Class Mitla (Locobase 6738)

Data from MexRy 1939 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works number was 6748.

Locobase is guessing about the reason for the longer boiler tubes in this engine, which is otherwise identical to the G-1s shown in Locobase 6737. It's likely to have been the result of a rebuilding later in its career.

Principal Dimensions by Steve Llanso of Middle Run Media
Class71G-1G-3G-3 / G-24GR-27
Locobase ID6740 6737 6742 13639 3236
RailroadMexican RailwayMexican RailwayMexican RailwayMexican RailwayMexican Railway
CountryMexicoMexicoMexicoMexicoMexico
Whyte2-8-02-8-02-8-02-8-02-8-0
Number in Class31016611
Road Numbers71-7354-60, 61-62 (2nd)/61-7090-10593-98200-210
GaugeStdStdStdStdStd
Number Built11014611
BuilderRhode IslandBurnham, Parry, Williams & CoBurnham, Williams & CoBurnham, Williams & CoBaldwin
Year18951881189919041921
Valve GearBakerStephensonStephensonStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15 / 4.5714.71 / 4.4814.25 / 4.3414.25 / 4.3414.25 / 4.34
Engine Wheelbase (ft / m)23 / 7.0122.62 / 6.8922.33 / 6.8122.33 / 6.8123.33 / 7.11
Ratio of driving wheelbase to overall engine wheelbase 0.65 0.65 0.64 0.64 0.61
Overall Wheelbase (engine & tender) (ft / m)53.25 / 16.2346.50 / 14.1752.92 / 16.1348.12 / 14.6756 / 17.07
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)143,812 / 65,23299,869 / 45,300129,830 / 58,890130,000 / 58,967171,000 / 77,564
Engine Weight (lbs / kg)156,645 / 71,053107,630 / 48,820142,814 / 64,779143,000 / 64,864193,000 / 87,543
Tender Loaded Weight (lbs / kg)120,000 / 54,43173,900 / 33,521120,000 / 54,43180,000 / 36,287120,000 / 54,431
Total Engine and Tender Weight (lbs / kg)276,645 / 125,484181,530 / 82,341262,814 / 119,210223,000 / 101,151313,000 / 141,974
Tender Water Capacity (gals / ML)6000 / 22.734000 / 15.156000 / 22.734000 / 15.156000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)2500 / 94632327 / 88082500 / 94632500 / 9463
Minimum weight of rail (calculated) (lb/yd / kg/m)60 / 3042 / 2154 / 2754 / 2771 / 35.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)50 / 127050 / 127050 / 127050 / 127051 / 1295
Boiler Pressure (psi / kPa)175 / 1210160 / 1100175 / 1210180 / 1240190 / 1310
High Pressure Cylinders (dia x stroke) (in / mm)20.5" x 26" / 521x66020" x 24" / 508x61020" x 26" / 508x66020" x 26" / 508x66022" x 28" / 559x711
Tractive Effort (lbs / kg)32,506 / 14744.4926,112 / 11844.2230,940 / 14034.1631,824 / 14435.1442,915 / 19465.94
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.42 3.82 4.20 4.08 3.98
Heating Ability
Tubes (number - dia) (in / mm)290 - 2" / 51178 - 2" / 51268 - 2" / 51237 - 2.25" / 57226 - 2" / 51
Flues (number - dia) (in / mm)32 - 5.375" / 137
Flue/Tube length (ft / m)13.60 / 4.1511.25 / 3.4313.37 / 4.0813.37 / 4.0813.84 / 4.22
Firebox Area (sq ft / m2)161 / 14.96177 / 16.44207.90 / 19.31167 / 15.51179 / 16.63
Grate Area (sq ft / m2)41 / 3.8128.10 / 2.6133.20 / 3.0933.20 / 3.0849.50 / 4.60
Evaporative Heating Surface (sq ft / m2)2167 / 201.391271 / 118.122047 / 190.242022 / 187.852425 / 225.37
Superheating Surface (sq ft / m2)511 / 47.49
Combined Heating Surface (sq ft / m2)2167 / 201.391271 / 118.122047 / 190.242022 / 187.852936 / 272.86
Evaporative Heating Surface/Cylinder Volume218.23145.59216.61213.97196.83
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation71754496581059769405
Same as above plus superheater percentage717544965810597611,004
Same as above but substitute firebox area for grate area28,17528,32036,38330,06039,792
Power L1436532934763453510,381
Power MT267.66290.77323.52307.63535.35

Principal Dimensions by Steve Llanso of Middle Run Media
ClassMitla
Locobase ID6738
RailroadMexican Railway
CountryMexico
Whyte2-8-0
Number in Class1
Road Numbers59/69
GaugeStd
Number Built
BuilderMexican
Year1882
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)14.79 / 4.51
Engine Wheelbase (ft / m)22.62 / 6.89
Ratio of driving wheelbase to overall engine wheelbase 0.65
Overall Wheelbase (engine & tender) (ft / m)46.67 / 14.23
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)99,869 / 45,300
Engine Weight (lbs / kg)107,630 / 48,820
Tender Loaded Weight (lbs / kg)73,900 / 33,521
Total Engine and Tender Weight (lbs / kg)181,530 / 82,341
Tender Water Capacity (gals / ML)4000 / 15.15
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)2327 / 8808
Minimum weight of rail (calculated) (lb/yd / kg/m)42 / 21
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)50 / 1270
Boiler Pressure (psi / kPa)150 / 1030
High Pressure Cylinders (dia x stroke) (in / mm)20" x 24" / 508x610
Tractive Effort (lbs / kg)24,480 / 11103.95
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.08
Heating Ability
Tubes (number - dia) (in / mm)198 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)13.25 / 4.04
Firebox Area (sq ft / m2)177 / 16.44
Grate Area (sq ft / m2)28.10 / 2.61
Evaporative Heating Surface (sq ft / m2)1551 / 144.14
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1551 / 144.14
Evaporative Heating Surface/Cylinder Volume177.66
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4215
Same as above plus superheater percentage4215
Same as above but substitute firebox area for grate area26,550
Power L13488
Power MT307.99

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