Sao Paulo 2-8-4 Locomotives in Brazil

Class Details by Steve Llanso of Sweat House Media

Class 84 (Locobase 20947)

Data from "New Locomotives on the San [sic] Paulo Ry.", Locomotive Magazine, Volume 37 (14 February 1931), p. 41. Works numbers were 23946-23961 in 1930.

Although relatively small for a standard-gauge 2-8-4, this sextet's small drivers, long side tanks, and full cab combined with a Belpaire firebox to imply considerable heft to the passerby. They were described in LM as intended for "moderate-speed heavy freight service", but the relatively small fuel and water capacities suggest banking or transfer freight duties.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID20947
RailroadSao Paulo
Number in Class6
Road Numbers84-89
Number Built6
BuilderNorth British
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.50 / 4.72
Engine Wheelbase (ft / m)35 / 10.67
Ratio of driving wheelbase to overall engine wheelbase 0.44
Overall Wheelbase (engine & tender) (ft / m)71.10 / 21.67
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)156,464 / 70,971
Engine Weight (lbs / kg)228,480 / 103,637
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)228,480 / 103,637
Tender Water Capacity (gals / ML)1800 / 6.82
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 3.30 / 3
Minimum weight of rail (calculated) (lb/yd / kg/m)65 / 32.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)51 / 1295
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)21.5" x 26" / 546x660
Tractive Effort (lbs / kg)40,062 / 18171.84
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.91
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)
Firebox Area (sq ft / m2)164 / 15.24
Grate Area (sq ft / m2)28.50 / 2.65
Evaporative Heating Surface (sq ft / m2)1599 / 148.55
Superheating Surface (sq ft / m2)430 / 39.95
Combined Heating Surface (sq ft / m2)2029 / 188.50
Evaporative Heating Surface/Cylinder Volume146.36
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5700
Same as above plus superheater percentage6897
Same as above but substitute firebox area for grate area39,688
Power L19786
Power MT551.55

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