Rede Mineira de Viacao 4-6-2 Locomotives in Brazil

Class Details by Steve Llanso of Sweat House Media

Class 339 (Locobase 6706)

Data from [] (last accessed 29 December 2009).

According to Jose Carlos Menezes' account 'O construtor das locomotivas de Divinopolis', published in the journal Central-Oeste no 4 (March 1985), these locomotives were developed on the railway when World War II dried up imports of engines from such sources as Baldwin or Alco in the USA.

The RMV took the then-drastic step of designing and building this pair in its own shops. The first try, rendered by the chief engineer, was predicted by its chief mechanic, Joao Morato, to fail. Sure enough, the locomotive, produced in 60 days, proved a "fiasco" when the locomotive was unable to move itself and its tender alone. The railway then allowed Joao Morato a "blank sheet". Morato responded by making over the failed engine, which resulted in the 339, a Pacific that worked. After tests showed the locomotive would deliver on its promise, Morato demonstrated a certain level of showmanship by moving the 339 to a neighboring city, coupling to the head of the overnight express and running triumphantly into Divinopolis.

Only two in the class were produced (because the supply problem eased?) and they served on southern and western lines. 3309 blew up its boiler in 1955, an accident attributed to poor maintenance. 340 saw out steam in 1965.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID6706
RailroadRede Mineira de Viacao
Number in Class
Road Numbers339-340
Number Built2
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m) 8.50 / 2.59
Engine Wheelbase (ft / m)24.14 / 7.36
Ratio of driving wheelbase to overall engine wheelbase 0.35
Overall Wheelbase (engine & tender) (ft / m)51.41 / 15.67
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)72,752 / 33,000
Engine Weight (lbs / kg)94,799 / 43,000
Tender Loaded Weight (lbs / kg)71,209 / 32,300
Total Engine and Tender Weight (lbs / kg)166,008 / 75,300
Tender Water Capacity (gals / ML)642 / 2.43
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)40 / 20
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)45.70 / 1160
Boiler Pressure (psi / kPa)182.70 / 12.60
High Pressure Cylinders (dia x stroke) (in / mm)14.02" x 21.93" / 356x557
Tractive Effort (lbs / kg)14,648 / 6644.23
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.97
Heating Ability
Tubes (number - dia) (in / mm)97 - 2.008" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)15.42 / 4.70
Firebox Area (sq ft / m2)114.49 / 10.64
Grate Area (sq ft / m2)22.27 / 2.07
Evaporative Heating Surface (sq ft / m2)1232 / 114.47
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1232 / 114.47
Evaporative Heating Surface/Cylinder Volume314.41
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4069
Same as above plus superheater percentage4069
Same as above but substitute firebox area for grate area20,917
Power L16408
Power MT582.55

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