Buenos Aires Pacific 4-6-0 Locomotives in Argentina


Class Details by Steve Llanso of Sweat House Media

Class 121-126 (Locobase 3664)

Data provided by Carlos Alberto Fern+ndez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (April 2000).


Class 81-86 (Locobase 3665)

Data provided by Carlos Alberto Fern+ndez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (April 2000).

The BAP operated 1,166 miles of track and was counted as one of the Big Four in Argentina.

Principal Dimensions by Steve Llanso of Sweat House Media

Class121-12681-86
Locobase ID3664 3665
RailroadBuenos Aires Pacific (BAP)Buenos Aires Pacific (BAP)
CountryArgentinaArgentina
Whyte4-6-04-6-0
Number in Class66
Road Numbers121-12681-86
Gauge5'6"5'6"
Number Built66
BuilderNorth BritishDubs & Co
Year19031902
Valve Gear
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)
Weight on Drivers (lbs / kg)112,560 / 51,05686,016 / 39,016
Engine Weight (lbs / kg)
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)3300 / 12.504095 / 15.51
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 5.60 / 57 / 6
Minimum weight of rail (calculated) (lb/yd / kg/m)63 / 31.5048 / 24
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)67 / 170267 / 1702
Boiler Pressure (psi / kPa)178.40 / 12.30179.80 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)21" x 26" / 533x66018" x 26" / 457x660
Tractive Effort (lbs / kg)25,951 / 11771.1919,216 / 8716.24
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.34 4.48
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)13 / 3.9612.42 / 3.79
Firebox Area (sq ft / m2)
Grate Area (sq ft / m2)30 / 2.7924 / 2.23
Evaporative Heating Surface (sq ft / m2)2215 / 205.861364 / 126.77
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)2215 / 205.861364 / 126.77
Evaporative Heating Surface/Cylinder Volume212.51178.12
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation53524315
Same as above plus superheater percentage53524315
Same as above but substitute firebox area for grate area
Power L1
Power MT

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