Data from "New Tank Locomotives, Highland Railway", The Locomotive Magazine, Vol XII (15 March 1906), p. 46; and "The Highland Railway and Its Locomotives", Locomotive Magazine, Volume XXV [25] (15 March 1919), p. 37.
The LM report noteds these two locomotives were designed by Peter Drummond and delivered in 1905. Their names were Strathpeffer and Gordon Lennox. Two more unnamed locomotives were delivered in 1906.
LM's 1919 overview explained that Drummond answered a requirement for smaller locomotives to serve local service on some newly acquired branch lines. 25 worked the Strathpeffer branch while the 40 replaced the old 118 on the Fochabler branch.
In 1920, the first two locomotives were rostered with only their numbers and in 1923 all four were taken into the London, Midland & Scottish with a power classificatgion of 0P.
The 15052 retired in December 1930 and the 15054 went in October 1945. When the 15051 and 15053 were renumbered in 1948, they were sent to operate on the Dornoch Light Railway. This 7-mile (11.3 km) railway connected the Highland's station at The Mound (at the head of Loch Fleet and almost 60 miles/95 km NE of Inverness) southeast to Dornoch on the North Sea.
55051 was retired in July 1956 and 55053 in January 1957.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | W |
| Locobase ID | 10552 |
| Railroad | Highland |
| Country | Great Britain |
| Whyte | 0-4-4T |
| Number in Class | 2 |
| Road Numbers | 25, 40, 45-46/15051-15054/55051, 55053 |
| Gauge | Std |
| Number Built | 2 |
| Builder | Lochgorm |
| Year | 1905 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 6 |
| Engine Wheelbase (ft / m) | 18.25 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.33 |
| Overall Wheelbase (engine & tender) (ft / m) | 18.25 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 25,200 |
| Weight on Drivers (lbs / kg) | 48,160 |
| Engine Weight (lbs / kg) | 79,520 / 35,562 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | 79,520 / 35,562 |
| Tender Water Capacity (gals / ML) | 1080 / 4.09 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 1.90 / 1 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 40 / 20 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 54 / 1372 |
| Boiler Pressure (psi / kPa) | 150 / 1030 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 14" x 20" / 356x508 |
| Tractive Effort (lbs / kg) | 9256 / 4198.46 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.20 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 170 - 1.75" / 0 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 8.48 |
| Firebox Area (sq ft / m2) | 67.50 / 6.27 |
| Grate Area (sq ft / m2) | 13 / 1.21 |
| Evaporative Heating Surface (sq ft / m2) | 720 / 66.91 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 720 / 66.91 |
| Evaporative Heating Surface/Cylinder Volume | 202.06 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 1950 |
| Same as above plus superheater percentage | 1950 |
| Same as above but substitute firebox area for grate area | 10,125 |
| Power L1 | 4006 |
| Power MT | 366.77 |