The first Stephenson engine with angled cylinders, which drove the leading axle directly, and thus a pathfinder toward the more efficient layout of cylinders and driving gear. Also fitted with a variable cut-off valve gear that actually worked in reverse, using an early cut-off when starting in order to save steam generated in the inadequate boiler. The boiler was a hybrid, intermediate step between a single flue and the later multi-tube having a central flue, 2 smaller return flues, and 2 water-tubes within the central flue.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | Lancashire Witch |
| Locobase ID | 633 |
| Railroad | Bolton & Leigh |
| Country | Great Britain |
| Whyte | 0-4-0 |
| Number in Class | 1 |
| Road Numbers | |
| Gauge | Std |
| Number Built | 1 |
| Builder | Robert Stephenson & Co |
| Year | 1828 |
| Valve Gear | |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 5 / 1.52 |
| Engine Wheelbase (ft / m) | 5 / 1.52 |
| 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) | 15,435 / 7001 |
| Engine Weight (lbs / kg) | 15,435 / 7001 |
| 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) | 13 / 6.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 48 / 1219 |
| Boiler Pressure (psi / kPa) | |
| High Pressure Cylinders (dia x stroke) (in / mm) | 9" x 24" / 229x610 |
| Tractive Effort (lbs / kg) | |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | |
| Firebox Area (sq ft / m2) | |
| Grate Area (sq ft / m2) | 12 / 1.12 |
| Evaporative Heating Surface (sq ft / m2) | 66 / 6.13 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 66 / 6.13 |
| Evaporative Heating Surface/Cylinder Volume | 37.35 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | |
| Same as above plus superheater percentage | |
| Same as above but substitute firebox area for grate area | |
| Power L1 | |
| Power MT | |