Data from "New Locomotive for the Llanelly and Mynydd Mawr Railway, Feilden's Magazine, An Engineering Review (C Edgar Allen, Ed.), Vol 7, No 6 (December 1902), p. 535. "Llanelly and Mynydd Mawr Railway Tank Locomotive," Locomotive Magazine, Vol VIII (3 Jan 1903), p. 11.
This 13-mile (20.9 km) Welsh mountain road skirted mountains on curves with 4-5 chains (264-330 ft) radii and grades approaching 2.5%. So the locomotive had to be strong enough to pull 207 tons of train (36 wagons) while bending around the sharp curves. Such flexibility was allowed by using a Cortazzi transaxle axle box that allowed not only 1 1/2" of lateral play (no small amount in itself), but also some vertical movement. The coupling rods had both horizontal and vertical joints; the lead axle had a ball and socket joint.
From 1883 to 1989, the line continued in use for coal traffic under the LMMR herald as well as that of the Great Western (1922-1948) and British Railways/British Rail thereafter.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | unknown |
| Locobase ID | 10253 |
| Railroad | Llanelly & Mynydd Mawr |
| Country | Great Britain |
| Whyte | 0-6-0T |
| Number in Class | 1 |
| Road Numbers | |
| Gauge | Std |
| Number Built | 1 |
| Builder | Avonside |
| Year | 1902 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 12 / 3.66 |
| Engine Wheelbase (ft / m) | 12 / 3.66 |
| Ratio of driving wheelbase to overall engine wheelbase | 1 |
| Overall Wheelbase (engine & tender) (ft / m) | 12 / 3.66 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 97,440 / 44,198 |
| Engine Weight (lbs / kg) | 97,440 / 44,198 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | 97,440 / 44,198 |
| Tender Water Capacity (gals / ML) | 1080 / 4.09 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 1.40 / 1 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 54 / 27 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 48 / 1219 |
| Boiler Pressure (psi / kPa) | 160 / 1100 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 17" x 24" / 432x610 |
| Tractive Effort (lbs / kg) | 19,652 / 8914.01 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.96 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | |
| Firebox Area (sq ft / m2) | 88 / 8.18 |
| Grate Area (sq ft / m2) | 16.50 / 1.53 |
| Evaporative Heating Surface (sq ft / m2) | 941 / 87.42 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 941 / 87.42 |
| Evaporative Heating Surface/Cylinder Volume | 149.25 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 2640 |
| Same as above plus superheater percentage | 2640 |
| Same as above but substitute firebox area for grate area | 14,080 |
| Power L1 | 2804 |
| Power MT | 190.32 |