FC Santa Fe 4-6-2 Locomotives in Argentina

Class Details by Steve Llanso of Sweat House Media

Class XII (Locobase 3744)

Data from Carlos Alberto Fernández Priotti in Bryan Attewell ([] Steam Locomotive simulator program (April 2000). See also Carlos A. Perez Darnaud, "La Clase Duodecima del Ferrocarril Provincial de Santa Fe", archived on [], last accessed 18 April 2010; and Andres J Bilstein, "Breves de Vapor: las duodecimas de FC Santa Fe", posted 16 enero 2016 on the Portal de Trenes at [], last accessed 22 October 2022. Works numbers were 61444-61463 in 1919 and 62925-62934 in 1921.

Fernandez notes that although these Pacifics had a relatively low axle loading, they were very successful. Perez commented that although the Santa Fe normally assigned even numbers to its passenger-service classes and odd-number class IDs to its freight engines, the duodecimals pulled as much freight as passenger trains in their long careers. Considered among the most attractive steam locomotives to graced Argentine narrow-gauge rails, this relatively small group of locomotives could be seen almost anywhere performing almost any kind of service.

Bumped from service area to service area as electrification and dieselization proceeded, the class nevertheless continued in service until the 1970s. To the very end, the 12s remained the classic iron-horse-of-all-trades as Perez's listing of its 1970s duties indicates:

Local passenger service between Santa Fe and Laguna Paiva 1

Mixed-train operation from Santa Fe through Tostado and Avia Terai to Resistencia and between Santa Fe and Villa, Maria and San Francisco, and Buenos Aires and Pergamino

Switching services in the Santa Fe zone

* Carga y hacienda (not sure what "hacienda" would mean here) entre Tapiales y CarhuT

And occasional service on ex Compañfa General lines.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID3744
RailroadFC Santa Fe (FCSF)
Number in Class30
Road Numbers651-680 / 4651-4680
Number Built30
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)
Engine Wheelbase (ft / m)
Ratio of driving wheelbase to overall engine wheelbase
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)19,987 / 9066
Weight on Drivers (lbs / kg)59,961 / 27,198
Engine Weight (lbs / kg)107,361 / 48,698
Tender Loaded Weight (lbs / kg)89,728 / 40,700
Total Engine and Tender Weight (lbs / kg)197,089 / 89,398
Tender Water Capacity (gals / ML)2859 / 13
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)11 / 10
Minimum weight of rail (calculated) (lb/yd / kg/m)33 / 16.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)49.30 / 1251
Boiler Pressure (psi / kPa)179.80 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)15.98" x 20" / 406x508
Tractive Effort (lbs / kg)15,832 / 7181.28
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.79
Heating Ability
Tubes (number - dia) (in / mm)90 - 2.008" / 51
Flues (number - dia) (in / mm)14 - 5.394" / 137
Flue/Tube length (ft / m)14.07 / 4.29
Firebox Area (sq ft / m2)83.96 / 7.80
Grate Area (sq ft / m2)24.22 / 2.25
Evaporative Heating Surface (sq ft / m2)1047 / 97.27
Superheating Surface (sq ft / m2)237 / 22.02
Combined Heating Surface (sq ft / m2)1284 / 119.29
Evaporative Heating Surface/Cylinder Volume225.52
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4355
Same as above plus superheater percentage5139
Same as above but substitute firebox area for grate area17,813
Power L111,455
Power MT1263.52

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