Buenos Aires Midland 2-6-4 Locomotives in Argentina

Class Details by Steve Llanso of Sweat House Media

Class G (Locobase 20413)

Data from "2-6-4 Tank Locomotive, Buenos Ayres [sic] Midland Ry.", Locomotive Magazine, Volume XXI [21] (15 January 1915), p. 4.

The BAM used 80-lb/yd (40 kg/metre) rail and added these tanks to spread the load of a larger boiler. Inside-admission piston valves supplied superheated steam to the cylinders and the Belpaire firebox gave it a typically squared-off look. Its firebox was one of the largest in a metre-gauge tank locomotive.

The class served suburban traffic until the system electrified in the late 1930s.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID20413
RailroadBuenos Aires Midland
Number in Class5
Road Numbers201
Number Built5
BuilderHunslet Engine Co
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)11 / 3.35
Engine Wheelbase (ft / m)30 / 9.14
Ratio of driving wheelbase to overall engine wheelbase 0.37
Overall Wheelbase (engine & tender) (ft / m)30 / 9.14
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)
Engine Weight (lbs / kg)128,800 / 58,423
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)128,800 / 58,423
Tender Water Capacity (gals / ML)3300 / 12.50
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 6.10 / 6
Minimum weight of rail (calculated) (lb/yd / kg/m)
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)54 / 1372
Boiler Pressure (psi / kPa)150 / 10.30
High Pressure Cylinders (dia x stroke) (in / mm)17" x 24" / 432x610
Tractive Effort (lbs / kg)16,377 / 7428.49
Factor of Adhesion (Weight on Drivers/Tractive Effort)
Heating Ability
Tubes (number - dia) (in / mm)97 - 1.75" / 44
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)11.80 / 3.60
Firebox Area (sq ft / m2)121 / 11.24
Grate Area (sq ft / m2)16 / 1.49
Evaporative Heating Surface (sq ft / m2)813 / 75.53
Superheating Surface (sq ft / m2)206 / 19.14
Combined Heating Surface (sq ft / m2)1019 / 94.67
Evaporative Heating Surface/Cylinder Volume128.95
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2400
Same as above plus superheater percentage2880
Same as above but substitute firebox area for grate area21,780
Power L17006
Power MT

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