An Opportunity Arises
In the early 1950s Robert Riddles was the British Railways (BR) Executive for Mechanical and Electrical Engineering and he was responsible for the introduction of a range of simple, two cylinder standardised steam locomotives intended to be in service until the 1970’s. These locomotives became know as BR Standards and 998 locomotives within 11 different classes were built between 1951 and 1960. The Duke took the number of classes to 12 and total BR Standards built to 999.
The first BR Standard class of locomotive to be built were 4-6-2 Class 7MT (Mixed Traffic) which filled the British loading gauge i.e. built to maximum height and width. There was no need for a new range of express passenger locomotives (Class 8P) as the private railway companies, which had been nationalised in 1947, had left the newly formed British Railways well provided for. However, an unfortunate accident at Harrow in 1952 resulted in the scrapping of one of the ex-LMS Pacific class locomotives, which thus presented Riddles with an opportunity to design a prototype for the future.
Designing The Duke
The Duke was designed at Derby locomotive works in 1953 and was constructed at Crewe locomotive works in 1954. After approximately eight years’ service during which the locomotive enjoyed, at best, a mixed reputation on the main line, it was withdrawn and sent for scrap.
That bald story, although correct, gives no clue as to what makes The Duke unique and why it holds such a special place in the history of steam locomotive development in Great Britain. “Unique” is a much overused word in connection with many artefacts, but this particular locomotive probably better earns that epithet than any other.
The table along side this text compares The Duke with the Britannia Class. There are only a few differences but chief amongst them is the valve gear.
| The Duke | Britannia | |
|---|---|---|
| Wheel Configuration | 4-6-2 (Pacific) | 4-6-2 (Pacific) |
| UIC Cclassification | 2′C1′h3 | 2′C1′h2 |
| Gauge | 4 ft 8 1⁄2 in (1435 mm) | 4 ft 8 1⁄2 in (1435 mm) |
| Leading Wheel Diameter | 3 ft 0 in (0.914 m) | 3 ft 0 in (0.914 m) |
| Driver Diameter | 6 ft 2 in (1.880 m) | 6 ft 2 in (1.880 m) |
| Trailing Wheel Diameter | 3 ft 3 1⁄2 in (1.003 m) | 3 ft 3 1⁄2 in (1.003 m) |
| Length | 67 ft 8 in (20.62 m) | 68 ft 9 in (20.96 m) |
| Width | 9 ft 0 in (2.74 m) | 8 ft 8 3⁄4 in (2.66 m) |
| Height | 13 ft 0 1⁄2 in (3.98 m) | 13 ft 0 1⁄2 in (3.98 m) |
| Axle Load | 22.00 long tons (22.35 t) | 20.50 long tons (20.83 t) |
| Weight on Driver Wheels | 66.00 long tons (67.06 t) | 61.50 long tons (62.49 t) |
| Locomotive Weight | 101.25 long tons (102.87 t) | 94.00 long tons (95.51 t) |
| Tender Weight | BR1E: 55.50 long tons (56.39 t) | 49.15 long tons (49.94 t) |
| BR1J: 53.70 long tons (54.56 t) | ||
| Tender Type | 1954–1958: BR1E | BR1 |
| 1958–1962: BR1J | ||
| Fuel Type | Coal | Coal |
| Fuel Capacity | 10 long tons (10 t) | 7.0 long tons (7.1 t) |
| Water Capacity | BR1E: 4725 imp gal (21480 l; 5674 US gal) | 4,250 imp gal (19,300 l; 5,100 US gal) |
| BR1J: 4325 imp gal (19660 l; 5194 US gal) | ||
| Boiler | BR13 | BR1 |
| Boiler Pressure | 250 psi (1.72 MPa) | 250 psi (1.72 MPa) |
| Firegrate Area Heating Surface | 48.6 sq ft (4.52 m2) | 42 sq ft (3.9 m2) |
| Tubes and Flues | 2264 sq ft (210.3 m2) | 2,264 sq ft (210.3 m2) |
| Firebox | 226 sq ft (21.0 m2) | 210 sq ft (20 m2) |
| Superheater Area | 677 sq ft (62.9 m2) | 718 sq ft (66.7 m2) |
| Number of Cylinders | Three, two outside + one inside | Two, outside |
| Cylinder Size | 18 in × 28 in (457 mm × 711 mm) | 20 in × 28 in (508 mm × 711 mm) |
| Valve Gear | Caprotti | Walschaerts |
| Chimney Type | Double | Single |