Brazil National Railways 2-8-4 Locomotives in Brazil


Class Details by Steve Llanso of Sweat House Media

Class 142N (Locobase 1129)

Data from Thierry Stora, whose website on French Compound Locomotives supplies this infomation, also supplied much of the data; and "2-8-4" in Wikipedia at [link], last accessed 15 March 2024. See also the discussion on the NARchive site [link] .Sixty-six engines built by the GELSA consortium starting with (Fives-Lille as works numbers were 5235-5256 in 1950-1951, Schneider-Creusot works numbers were 4538-4952 in 1951, and Cail (works numbers were 4473-4494 in 1952).

These were designed along the same lines as the Chapelon 4-8-4 (Locobase 1127)), but much smaller and less demanding on the machinery.

Representative of the operational constraints imposed on the builders, the class had to travel over 22 kg/metre (44 lb/yard) rail. Depending on the railway, a 142N used one of three tenders, including one that carried firewood instead of brown coal.

Wikipedia summarized their capacities as follows:

Heavy tender six-wheel bogies carried 12 metric tons of coal and 17,,800 litres (3,900 imperial gallons; 4,700 US gallons) of water.. Light coal tenders rolled on four-wheel bogies, had a coal capacity of 7 tons and a water capacity of 6,900 litres (1,500 imperial gallons; 1,800 US gallons). The tender used by wood burners also used four-wheel bogies, a firewood capacity of 7 cubic metres (250 cubic feet) and the least water capacity at 6,400 litres (1,400 imperial gallons; 1,700 US gallons).

Still, like the 4-8-4s, they had trouble on the very tight curves (50 m minimum as opposed to the specified 80 m) and were limited to 38 mph (60 kph). The engines struggled for acceptance, being viewed as "too modern"

Principal Dimensions by Steve Llanso of Middle Run Media
Class142N
Locobase ID1129
RailroadBrazil National Railways
CountryBrazil
Whyte2-8-4
Number in Class66
Road Numbers1-22; 23-25, 48-66; 26-47
GaugeMetre
Number Built66
BuilderGroupement d'Exportation de Locomotives SA (GELSA)
Year1951
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.48 / 4.11
Engine Wheelbase (ft / m)30.25 / 9.22
Ratio of driving wheelbase to overall engine wheelbase 0.45
Overall Wheelbase (engine & tender) (ft / m)71.10 / 21.67
Axle Loading (Maximum Weight per Axle) (lbs / kg)22,046 / 10,000
Weight on Drivers (lbs / kg)89,071 / 40,402
Engine Weight (lbs / kg)154,323 / 70,000
Tender Loaded Weight (lbs / kg)160,386 / 72,750
Total Engine and Tender Weight (lbs / kg)314,709 / 142,750
Tender Water Capacity (gals / ML)4699 / 17.80
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 7.70 / 7
Minimum weight of rail (calculated) (lb/yd / kg/m)37 / 18.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)50 / 1270
Boiler Pressure (psi / kPa)217.60 / 1500
High Pressure Cylinders (dia x stroke) (in / mm)17.01" x 22.05" / 432x560
Tractive Effort (lbs / kg)23,601 / 10705.25
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.77
Heating Ability
Tubes (number - dia) (in / mm)88 - 2.008" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)15.26 / 4.65
Firebox Area (sq ft / m2)212.05 / 19.70
Grate Area (sq ft / m2)43.06 / 4
Evaporative Heating Surface (sq ft / m2)1315 / 122.21
Superheating Surface (sq ft / m2)484 / 44.98
Combined Heating Surface (sq ft / m2)1799 / 167.19
Evaporative Heating Surface/Cylinder Volume226.74
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9370
Same as above plus superheater percentage11,900
Same as above but substitute firebox area for grate area58,600
Power L121,047
Power MT2083.76

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