See Talyllyn for full details on the railway. Dolgoch has a long wheelbase, which allowed the firebox to be placed ahead of the rear axle. But, [] ... adds, this also meant the "Fletcher's Patent inside valve gear [was] driven off the front axle, a particularly inacessible arrangement."
On Dolgoch soldiered, wearing down as it was the only engine operation after Talyllyn was retired in 1945. In 1954-1963, it was the subject of an extensive overhaul. Later repairs, which ended in 1999, fixed the firebox, overhauled the engine mechanically, and, at last, installed air brakes.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | Pretoria/Dolgoch |
| Locobase ID | 4916 |
| Railroad | Talyllyn Railway |
| Country | Great Britain |
| Whyte | 0-4-0T |
| Number in Class | 1 |
| Road Numbers | 2 |
| Gauge | 2'3" |
| Number Built | 1 |
| Builder | Fletcher, Jennings & Co |
| Year | 1866 |
| Valve Gear | Fletcher Patent |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 6 / 1.83 |
| Engine Wheelbase (ft / m) | 6 / 1.83 |
| Ratio of driving wheelbase to overall engine wheelbase | 1 |
| Overall Wheelbase (engine & tender) (ft / m) | |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 22,960 / 10,414 |
| Engine Weight (lbs / kg) | 22,960 / 10,414 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 19 / 9.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 24 / 711 |
| Boiler Pressure (psi / kPa) | 150 / 1030 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 8.75" x 16" / 194x406 |
| Tractive Effort (lbs / kg) | 6508 / 2951.98 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.53 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 60 - 1.5" / 0 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | |
| Firebox Area (sq ft / m2) | |
| Grate Area (sq ft / m2) | 4 |
| Evaporative Heating Surface (sq ft / m2) | 128 / 11.90 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 128 / 11.90 |
| Evaporative Heating Surface/Cylinder Volume | 114.95 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 600 |
| Same as above plus superheater percentage | 600 |
| Same as above but substitute firebox area for grate area | |
| Power L1 | |
| Power MT | |