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 Middle Run Media | |
|---|---|
| Class | Double Fairlie |
| Locobase ID | 2723 |
| Railroad | Bolivian State |
| Country | Bolivia |
| Whyte | 0-6+6-0 |
| Number in Class | |
| Road Numbers | |
| Gauge | 2'6" |
| Number Built | |
| Builder | Yorkshire Engine |
| Year | 1906 |
| Valve Gear | Walschaert |
| 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 / 1100 |
| 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 Volume | 230.36 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 3440 |
| Same as above plus superheater percentage | 3440 |
| Same as above but substitute firebox area for grate area | |
| Power L1 | |
| Power MT | |