GWR 3252 Class

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GWR Duke class
Didcot Duke geograph-2514380-by-Ben-Brooksbank.jpg
No. 9083 Comet at Didcot in 1948
Type and origin
Power type Steam
Designer William Dean
Builder GWR Swindon Works
Build date 1895–1899
Specifications
Configuration 4-4-0
UIC classification 2'B ht
Gauge 4 ft 8 12 in (1,435 mm)
Leading wheel
diameter
3 ft 8 in (1.118 m)
Driver diameter 5 ft 8 in (1.727 m)
Axle load 15 long tons 7 cwt (34,400 lb or 15.6 t) full
Locomotive weight 46 long tons 0 cwt (103,000 lb or 46.7 t) full
Tender weight 24 long tons 0 cwt (53,800 lb or 24.4 t) full
Locomotive and tender
combined weight
70 long tons 0 cwt (156,800 lb or 71.1 t) full
Fuel type Coal
Boiler pressure 160 lbf/in2 (1.1 MPa)
Heating surface:
– Tubes
1,285.58 sq ft (119.434 m2)
– Firebox 115.27 sq ft (10.709 m2)
Cylinders Two, inside
Cylinder size 18 in × 26 in (457 mm × 660 mm)
Valve gear Stephenson
Performance figures
Train brakes Vacuum
Career
Operator(s) GWR » BR
Withdrawn 1929-1951

The Great Western Railway 3252 or Duke Class were 4-4-0 steam locomotives with outside frames and parallel domed boilers.[1] 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.[1] Four prototype 4-4-0s, of the Armstrong Class, had already been built in 1894.[2]

Design[edit]

Frames and wheels[edit]

The outside frames of the Dukes were curved upwards over each pair of driving wheels. Inner and outer frames were 34 in (1.9 cm) thick.[3] The first 40 members of the class were fitted with Mansell pattern bogie wheels with wooden centres.[4] The first 25 tenders built also had Mansell pattern wheels, and a shorter than normal wheelbase of 11 ft (3.4 m) so that the locomotives would fit on the smaller turntables then in use west of Newton Abbot.[4] The engine bogie was of a centre-less type designed by Dean.[5]

Boilers[edit]

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.[6] Eighteen of the Duke class were later rebuilt with domeless tapered boilers and Belpaire fireboxes between October 1906 and January 1909.[7] 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.[7] By December 1923 all remaining Dukes had been fitted with flush-topped Belpaire fireboxes and domed boilers pressed to 180 lbf/in2 (1.2 MPa).[8] 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.[9] The class had distinctive long smokeboxes, extended to hold a diaphragm plate and net for spark prevention.[4]

Cylinders and valves[edit]

Slide valves were fitted underneath the cylinders, and were driven directly by eccentrics on the leading driving axle through Stephenson valve gear.[5][10] 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 17 in (43.2 cm) to 20 in (50.8 cm) in the Armstrong Class.[11] The Dukes had 18 in (45.7 cm) diameter cylinders, possibly due to permanent way weight restrictions and a reduced supply of steam from the Dukes' smaller boilers.[4]

Renumbering[edit]

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[edit]

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.[12] 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.[13]

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.[13]

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.[14] 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.[15]

Summary table[edit]

Numbers Names
First Second Third First Second
3252 3252 Earl 3214 Duke of Cornwall
3253 Bulldog 3300 Pendennis Castle
3254 3253 Earl 3223 Boscawen
3255 3254 9054 Cornubia
3256 3255 Earl 3205 Excalibur
3257 3256 Earl 3228 Guinevere
3258 3257 Earl 3213 King Arthur Denamed in 1927
3259 3258 Earl 3217 Lizard The Lizard
3260 3259 Earl 3221 Merlin
3261 3260 Earl 3219 Mount Edgcumbe
3262 Bulldog 3301 Powderham
3263 Bulldog 3302 Sir Lancelot
3264 Bulldog 3303 St. Anthony
3265 3261 Earl 3212 St. Germans
3266 3262 Earl 3215 St. Ives
3267 3263 Earl 3201 St. Michael
3268 Bulldog 3304 Tamar River Tamar
3269 Bulldog 3305 Tintagel
3270 3264 9064 Trevithick
3271 3265 Earl 3265 Tre Pol and Pen
3272 3266 Earl 3218 Amyas
3273 Bulldog 3306 Armorel
3274 3267 Earl 3206 Cornishman
3275 3268 Earl 3225 Chough
3276 3269 Earl 3210 Dartmoor
3277 3270 Earl 3226 Earl of Devon Denamed in 1930
3278 3271 Earl 3204 Eddystone
3279 Bulldog 3307 Exmoor
3280 Bulldog 3308 Falmouth
3281 3272 9072 Fowey Denamed in 1930
3282 Bulldog 3309 Maristowe
3283 3273 9073 Mount's Bay
3284 3274 Earl 3207 Newquay Denamed in 1930
3285 3275 Earl 3203 St. Erth Denamed in 1930
3286 Bulldog 3310 St. Just
3287 3276 9076 St. Agnes Denamed in 1930
3288 3277 Earl 3209 Tresco Isle of Tresco
3289 3278 Earl 3222 Trefusis
3290 3279 Earl 3220 Torbay Tor Bay
3291 3280 Earl 3227 Tregenna Denamed in 1930
3312 Bulldog 3311 Bulldog
3313 3281 Earl 3211 Cotswold
3314 3282 Earl 3216 Chepstow Castle Denamed in 1930
3315 3283 9083 Comet
3316 Bulldog 3312 Guernsey Isle of Guernsey
3317 3284 9084 Jersey Isle of Jersey
3318 Bulldog 3313 Jupiter
3319 3285 Earl 3208 Katerfelto
3320 3286 Earl 3202 Meteor
3321 3287 9087 Mercury
3322 Bulldog 3314 Mersey
3323 3288 Earl 3200 Mendip
3324 Bulldog 3315 Quantock
3325 Bulldog 3316 St. Columb
3326 3289 9089 St Austell Denamed in 1930
3327 Bulldog 3317 Somerset
3328 3290 Earl 3224 Severn
3329 3291 9091 Thames
3330 Bulldog 3318 Vulcan
3331 Bulldog 3319 Weymouth

References[edit]

  1. ^ a b Nock 1977, p. 16
  2. ^ Nock 1977, p. 9
  3. ^ Nock 1977, p. 78
  4. ^ a b c d Nock 1977, p. 17
  5. ^ a b Nock 1977, p. 27
  6. ^ Nock 1977, p. 29
  7. ^ a b Nock 1977, p. 77
  8. ^ Nock 1978, p. 70
  9. ^ Nock 1978, p. 87
  10. ^ Nock 1977, p. 10
  11. ^ Nock 1977, p. 11
  12. ^ Nock 1978, p. 73
  13. ^ a b Nock 1978, p. 74
  14. ^ Nock 1977, p. 30
  15. ^ Nock 1978, p. 75

Bibliography[edit]