Mexicano del Sur 4-6-0 Locomotives in Mexico

Class Details by Steve Llanso of Sweat House Media

Class F-05 (Locobase 9960)

Data from "Narrow Gauge Engine for the Mexican Southern", Railway and Locomotive Engineering, Volume XV [15], No 9 (September 1902), p. 391; "Locomotives for the Mexican Southern", Railway Master Mechanic, Volume 26, No 7 (July 1902), pp. 260. Works numbers were 25797-25798 in April 1902.

Outside-frame Ten-wheelers with slide valves, straight boilers and very similar to the Schenectady-built engines (Locobase 3238) delivered to the Interoceanic in 1898. Characterised by R&LE as heavy for the 3' gauge, the engine also sported a boiler with fewer, but larger-diameter tubes than most other skinny-gauge locomotives. The photograph shows unusually large bogie-truck wheels in relation to the driver diameter and a wide gap between the second and third drivers to accommodate the firebox.

Eventually passing into the hands of the Nacional de Mexico, the pair survived until 1954.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID9960
RailroadMexicano del Sur
Number in Class2
Road Numbers103-104/261-262
Number Built2
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.17 / 4.01
Engine Wheelbase (ft / m)22.08 / 6.73
Ratio of driving wheelbase to overall engine wheelbase 0.60
Overall Wheelbase (engine & tender) (ft / m)42.58 / 12.98
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)58,000 / 26,308
Engine Weight (lbs / kg)87,000 / 39,463
Tender Loaded Weight (lbs / kg)67,000 / 30,391
Total Engine and Tender Weight (lbs / kg)154,000 / 69,854
Tender Water Capacity (gals / ML)3000 / 11.36
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)5 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)32 / 16
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)47 / 1194
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)17" x 20" / 432x508
Tractive Effort (lbs / kg)16,725 / 7586.34
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.47
Heating Ability
Tubes (number - dia) (in / mm)134 - 2.25" / 57
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)11.58 / 3.53
Firebox Area (sq ft / m2)77 / 7.16
Grate Area (sq ft / m2)15.38 / 1.43
Evaporative Heating Surface (sq ft / m2)1054 / 97.96
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1054 / 97.96
Evaporative Heating Surface/Cylinder Volume200.76
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2461
Same as above plus superheater percentage2461
Same as above but substitute firebox area for grate area12,320
Power L13435
Power MT391.70

All material Copyright ©
Wes Barris