Bolivian State Articulated Locomotives in Bolivia

Class Details by Steve Llanso of Sweat House Media

Class Double Fairlie (Locobase 2723)

Data from "Fairlie Locomotive for the Bolivian Rys," The Locomotive Magazine, Vol XIII (15 January 1907), p. 7. See also Nock (RWC III, pl 138).

These modified Fairlie-type articulated engines had a boiler at each end, each one graced by a stack, sand dome and steam dome, and two Belpaire fireboxes facing each other in the single cab. The whole heating system rested on a single frame with both engine units on bogies, which greatly aided the locomotive's progress around the tight curves and narrow loading gauge.

Moreover, Yorkshire addressed the Fairlie's principal problem, which was the difficulty in making the large number of ball and socket joints steam tight.

Principal Dimensions by Steve Llanso of Sweat House Media

ClassDouble Fairlie
Locobase ID2723
RailroadBolivian State
Number in Class
Road Numbers
Number Built
BuilderYorkshire Engine
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)6 / 1.83
Engine Wheelbase (ft / m)29.37 / 8.95
Ratio of driving wheelbase to overall engine wheelbase 0.20
Overall Wheelbase (engine & tender) (ft / m)29.37 / 8.95
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)116,704 / 52,936
Engine Weight (lbs / kg)116,704 / 52,936
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)116,704 / 52,936
Tender Water Capacity (gals / ML)1800 / 6.82
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 2.20 / 2
Minimum weight of rail (calculated) (lb/yd / kg/m)32 / 16
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)30 / 762
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)12.5" x 16" / 318x406 (4)
Tractive Effort (lbs / kg)22,667 / 10281.59
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.15
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m) 9.31 / 2.84
Firebox Area (sq ft / m2)
Grate Area (sq ft / m2)21.50 / 2
Evaporative Heating Surface (sq ft / m2)1047 / 97.30
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1047 / 97.30
Evaporative Heating Surface/Cylinder Volume230.36
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3440
Same as above plus superheater percentage3440
Same as above but substitute firebox area for grate area
Power L1
Power MT

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