The Great Western Railway 3252 or Duke Class were 4-4-0 steam locomotives with outside frames and parallel domed boilers. They were built in five batches between 1895 and 1899 for express passenger train work in Devon and Cornwall. William Dean was their designer, possibly with the collaboration of his assistant, George Jackson Churchward. Four prototype 4-4-0s, of the Armstrong Class, had already been built in 1894.

Design Frames and wheels The outside frames of the Dukes were curved upwards over each pair of driving wheels. Inner and outer frames were thick. The first 40 members of the class were fitted with Mansell pattern bogie wheels with wooden centres. The first 25 tenders built also had Mansell pattern wheels, and a shorter than normal wheelbase of so that the locomotives would fit on the smaller turntables then in use west of Newton Abbot. The engine bogie was of a centre-less type designed by Dean.

Boilers The majority of the class were fitted with round-topped fireboxes of the same diameter as the boiler. The last four were fitted with Belpaire fireboxes, raised a few inches above the boilers. Eighteen of the Duke class were later rebuilt with domeless tapered boilers and Belpaire fireboxes between October 1906 and January 1909. They were reclassified as members of the Bulldog Class. A further Duke, no. 3273 Armorel, had been fitted with a parallel domeless boiler in February 1902, converting it to a Camel Class locomotive. It was fitted with a Bulldog-type boiler in October 1910. By December 1923 all remaining Dukes had been fitted with flush-topped Belpaire fireboxes and domed boilers pressed to . Duke no. 3258, King Arthur, built August 1895, was fitted with a superheater in December 1896. The rest of the class, with the exception of two locomotives, were fitted with superheaters between August 1911 and September 1946. The class had distinctive long smokeboxes, extended to hold a diaphragm plate and net for spark prevention.

Cylinders and valves Slide valves were fitted underneath the cylinders, and were driven directly by eccentrics on the leading driving axle through Stephenson valve gear. This position had the advantage that, when the regulator was closed and steam pressure shut off, the valves would drop away from the steam ports, thus reducing wear on the valves and port faces. Dean's earlier designs had used slide valves mounted vertically between the cylinders; the new position allowed an increase in cylinder diameter from to in the Armstrong Class. The Dukes had diameter cylinders, possibly due to permanent way weight restrictions and a reduced supply of steam from the Dukes' smaller boilers.

+ Table of orders and numbers Year Quantity Lot No. Works No. Locomotive numbers Notes 1895 2 97 1431–1432 3252–3253 1895 8 101 1493–1500 3254–3261 1896 10 102 1501–1510 3262–3271 1896–97 20 105 1531–1550 3272–3291 1898–99 20 113 1682–1701 3312–3331

Renumbering The Dukes were subject to the 1912 renumbering of GWR 4-4-0 locomotives. Those Dukes rebuilt as Bulldogs were renumbered as members of that class in the series 3300–3455. The remaining Dukes were renumbered consecutively as 3252–3291, this block of numbers having previously been allocated to the first batch of Duke Class locomotives.

Rebuilding By the 1930s many of the Duke class were becoming uneconomical to repair, particularly with regard to the curved outside frames, which were weaker than the later straight-topped version. A number of the class had been transferred to the ex-Cambrian Railways main line, where permanent way restrictions debarred the use of heavier locomotives.

In December 1929, no. 3265, Tre Pol and Pen, was withdrawn, and the cylinders and motion, together with a spare Duke boiler and smokebox, were fitted to the straight-topped frames and cab of Bulldog no. 3365 Charles Grey Mott. The rebuilt locomotive retained the name and number of the Duke. The reduction in axle weight, as compared to the Bulldogs, allowed for working over the Cambrian section.

From 1936 a further twenty-nine of the Dukes were withdrawn and replaced by Bulldogs fitted with Duke boilers and motion, reclassified as Earl Class locomotives. The onset of World War II brought a halt to the program, the last replacement being in November 1939, leaving ten Dukes to pass into British Railways ownership. These were scrapped between June 1949 and July 1951, the last survivor being No. 9089, formerly no. 3289 St Austell of July 1899.

In fiction The fate of the Dukes are mentioned by Duck the Great Western Engine in the Reverend Wilbert Awdry's children's book Very Old Engines.

Summary table NumbersNames First Second Third First Second32523252Earl 3214Duke of Cornwall3253Bulldog 3300Pendennis Castle32543253Earl 3223Boscawen325532549054Cornubia32563255Earl 3205Excalibur32573256Earl 3228Guinevere32583257Earl 3213King ArthurDenamed in 192732593258Earl 3217LizardThe Lizard32603259Earl 3221Merlin32613260Earl 3219Mount Edgcumbe3262Bulldog 3301Powderham3263Bulldog 3302Sir Lancelot3264Bulldog 3303St. Anthony32653261Earl 3212St. Germans32663262Earl 3215St. Ives32673263Earl 3201St. Michael3268Bulldog 3304TamarRiver Tamar3269Bulldog 3305Tintagel327032649064Trevithick32713265Earl 3265Tre Pol and Pen32723266Earl 3218Amyas3273Bulldog 3306Armorel32743267Earl 3206Cornishman32753268Earl 3225Chough32763269Earl 3210Dartmoor32773270Earl 3226Earl of DevonDenamed in 193032783271Earl 3204Eddystone3279Bulldog 3307Exmoor3280Bulldog 3308Falmouth328132729072FoweyDenamed in 19303282Bulldog 3309Maristowe328332739073Mount's Bay32843274Earl 3207NewquayDenamed in 193032853275Earl 3203St. ErthDenamed in 19303286Bulldog 3310St. Just328732769076St. AgnesDenamed in 193032883277Earl 3209TrescoIsle of Tresco32893278Earl 3222Trefusis32903279Earl 3220TorbayTor Bay32913280Earl 3227TregennaDenamed in 19303312Bulldog 3311Bulldog33133281Earl 3211Cotswold33143282Earl 3216Chepstow CastleDenamed in 1930331532839083Comet3316Bulldog 3312GuernseyIsle of Guernsey331732849084JerseyIsle of Jersey3318Bulldog 3313Jupiter33193285Earl 3208Katerfelto33203286Earl 3202Meteor332132879087Mercury3322Bulldog 3314Mersey33233288Earl 3200Mendip3324Bulldog 3315Quantock3325Bulldog 3316St. Columb332632899089St AustellDenamed in 19303327Bulldog 3317Somerset33283290Earl 3224Severn332932919091Thames3330Bulldog 3318Vulcan3331Bulldog 3319Weymouth

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