List of GWR standard classes with two outside cylinders

Standardization on the Great Western Railway started with Daniel Gooch, its first Locomotive Superintendent[lower-alpha 1], who enforced uniformity on third-party suppliers of parts by issuing lithographed copies of drawings and iron templates to check accurate fitting. This was carried through once the GWR built its own works at Swindon, and standard parts were also shared by different classes of locomotive. Joseph Armstrong (and his brother George) used similar techniques at Wolverhampton, and continued Gooch's policy when he replaced him at Swindon. William Dean, Armstrong's successor, designed (among others) four classes of locomotive, 2-4-0 and 0-6-0 tender and tank engines, which shared many standard components. However, it was George Jackson Churchward who carried the policy to lengths which made GWR locomotives distinctive and shaped their development until the the nationalization of the railways.[1]

Even before Churchward succeeded Dean as Locomotive Superintendent in 1902, he had in 1901 published a list of proposed new locomotive classes of a revolutionary nature.[2] He began by designing a range of standard components, then constructed a variety of locomotive designs of different sizes and purposes around these items.[3] These locomotives were to have two outside cylinders, inside frames and motion, generous piston valves, and identical left/right cylinder castings, and they shared three coupled wheel sizes, two standard boilers and a single size of leading/trailing wheel. When Churchward took over the job, he began to create prototypes to test and evaluate his ideas, and they were developed into a series of locomotive classes that appeared throughout Churchward's time in office, and were further developed and expanded by both Charles Collett and Frederick Hawksworth, his successors up to the end of the GWR. Indeed, the proposed 4-6-0 with 5 ft 8 in driving wheels did not appear until Collett built the Granges in 1936. Even after the GWR ceased to exist, a new 'class' of Mogul was developed on the West Somerset Railway.

Comparison of locomotive classes

This table summarises the classes that developed from Churchward's proposals. It is simplified in that it suggests the classes were sets of identical engines, whereas the prototypes often differed in some respects from later class members, and there was a constant move to improve the locomotives by changing boilers, enlarging cylinders and tweaking other details of their construction. By and large, the details and dimensions given were common to most members of the class in their final form. The details of Churchward's original proposed locomotives and boilers are shaded; no classes were built to exactly those dimensions. However, the proposed classes will sort adjacent to the most closely matching real classes. The WSR Mogul is shaded pink.

This table does not include

  • the 4-cylinder classes - Stars, Castles and Kings
  • similar looking inside-cylinder classes - 3900 2-6-2Ts, 5600 0-6-2Ts, and 2251 0-6-0s
  • non-standard classes - outside-cylindered ex-ROD 3000 2-8-0s
GWR standard classes with two outside cylinders
Class CME Year Wheel
arrangement		 Driving
wheel spacing		 Wheel diameters Cylinders Standard
boiler no.		 Boiler
pressure		 Tractive
effort		 Numbering Refs
Leading Driving Trailing Bore Stroke
Proposed 4‑6‑0 Churchward 1901 4-6-0 3 ft 3 in 6 ft 8 ½ in 18 in 30 in Prop 1 [4][5]
Proposed 4‑6‑0 Churchward 1901 4-6-0 3 ft 3 in 5 ft 8 in 18 in 30 in Prop 1 [4][5]
Proposed 4‑4‑2T Churchward 1901 4-4-2T 3 ft 3 in 6 ft 8½ in 3 ft 3 in 18 in 30 in Prop 2 [4][5]
Proposed 4‑4‑0 Churchward 1901 4-4-0 3 ft 3 in 6 ft 8½ in 18 in 30 in Prop 2 [4][5]
Proposed 2‑8‑0 Churchward 1901 2-8-0 3 ft 3 in 4 ft 7½ in 18 in 30 in Prop 1 [4][5]
Proposed 2‑6‑2T Churchward 1901 2-6-2T 3 ft 3 in 5 ft 8 in 3 ft 3 in 18 in 30 in Prop 2 [4][5]
2900 Saint Churchward 1902 4-6-0[lower-alpha 2] 7 ft / 7 ft 9 in 3 ft 2 in 6 ft 8½ in 18½ in 30 in 1 225 psi 24,395 lbf 2900-2955; 2971-2990; 2998 [7][8][9][10]
2800, 2884[lower-alpha 3] Churchward 1903 2-8-0 5 ft 5 in / 5 ft 5 in / 6 ft 3 ft 2 in 4 ft 7½ in 18½ in 30 in 1 225 psi 35,380 lbf 28xx, 3800-66 [12][8][13][14]
3100 (1903) Churchward 1903 2-6-2T 7 ft / 7 ft 9 in 3 ft 2 in 5 ft 8 in 3 ft 8 in 18 in 30 in 2 200 psi 24,300 lbf 3100, 3111-49; later renumbered 5100, 5111-49 [15][8]
3800 County Churchward 1904 4-4-0 8 ft 6 in 3 ft 2 in 6 ft 8½ in 18 in 30 in 4 200 psi 20,530 lbf 3473-82; renumbered 3800-39 [16][8][17]
4400 Churchward 1904 2-6-2T 6 ft / 5 ft 6 in 3 ft 2 in 4 ft 1½ in 3 ft 2 in 16½ in 24 in 5 180 psi 20,195 lbf 4400-10 [18][19]
2221 County Tank Churchward 1905 4-4-2T 8 ft 6 in 3 ft 2 in 6 ft 8½ in 3 ft 8 in 18 in 30 in 2 200 psi 20,530 lbf 2221-50 [20][8][21]
4500, 4575[lower-alpha 4] Churchward 1906 2-6-2T 5 ft 6 in / 6 ft 3 ft 2 in 4 ft 7½ in 3 ft 2 in 17 in 24 in 5 200 psi 21,250 lbf 2161-90; later renumbered 45xx, 5500-74 [23][8][24][25]
3150 Churchward 1906 2-6-2T 7 ft / 7 ft 9 in 3 ft 2 in 5 ft 8 in 3 ft 8 in 18½ in 30 in 4 200 psi 25,670 lbf 3150-90 [26][8][27]
4200 Churchward 1910 2-8-0T 7 ft / 6 ft / 7 ft 3 ft 2 in 4 ft 7½ in 18½ in 30 in 4 200 psi 31,450 lbf 42xx, 5200-04 [23][8][28]
4300 Mogul Churchward 1911 2-6-0 7 ft / 7 ft 9 in 3 ft 2 in 5 ft 8 in 18½ in 30 in 4 200 psi 25,670 lbf 43xx, 53xx, 63xx, 7300-21, 9300-21 [29][8][30][31]
4600 Churchward 1913 4-4-2T 7 ft 3 ft 2 in 5 ft 8 in 3 ft 2 in 17 in 24 in 5 200 psi 18,360 lbf 4600 [32]
4700 Churchward 1919 2-8-0 6 ft 6 in / 6 ft 6 in / 7 ft 3 ft 2 in 5 ft 8 in 19 in 30 in 7 225 psi 30,460 lbf 4700-08 [33][8][34][35]
5205 Collett 1923 2-8-0T 7 ft / 6 ft / 7 ft 3 ft 2 in 4 ft 7½ in 19 in 30 in 4 200 psi 33,170 lbf 5205-64 [36][37][38]
4900 Hall Collett 1924 4-6-0 7 ft / 7 ft 9 in 3 ft 6 ft 18½ in 30 in 1 225 psi 27,275 lbf 49xx, 59xx, 6900-58 [39][8][40][41]
5101 Collett 1929 2-6-2T 7 ft / 7 ft 9 in 3 ft 2 in 5 ft 8 in 3 ft 8 in 18 in 30 in 2 200 psi 24,300 lbf 5101-10, 5150-99, 4100-79 [42][8][43][44]
6100 Collett 1931 2-6-2T 7 ft / 7 ft 9 in 3 ft 2 in 5 ft 8 in 3 ft 8 in 18 in 30 in 2 225 psi 27,340 lbf 6100-69 [45][8][43][46]
7200 Collett 1934 2-8-2T 7 ft / 6 ft / 7 ft 3 ft 2 in 4 ft 7½ in 3 ft 8 in 19 in 30 in 4 200 psi 33,170 lbf 7200-53 [47][8][48]
6800 Grange Collett 1936 4-6-0 7 ft / 7 ft 9 in 3 ft 5 ft 8 in 18½ in 30 in 1 225 psi 28,875 lbf 6800-79 [49][8][50][51]
7800 Manor Collett 1938 4-6-0 7 ft / 7 ft 9 in 3 ft 5 ft 8 in 18 in 30 in 14 225 psi 27,340 lbf 7800-19 [52][8][53][54]
8100 Collett 1938 2-6-2T 7 ft / 7 ft 9 in 3 ft 5 ft 6 in 3 ft 8 in 18 in 30 in 2 225 psi 28,165 lbf 8100-09 [55][8][43][56]
3100 (1938) Collett 1938 2-6-2T 7 ft / 7 ft 9 in 3 ft 5 ft 3 in 3 ft 8 in 18½ in 30 in 4 225 psi 31,170 lbf 3100-04 [55][8][27][57][58]
6959 Modified Hall Hawksworth 1944 4-6-0 7 ft / 7 ft 9 in 3 ft 6 ft 18½ in 30 in 1 225 psi 27,275 lbf 6959-99, 7900-29 [59][8][40][60]
1000 County Hawksworth 1945 4-6-0 7 ft / 7 ft 9 in 3 ft 6 ft 3 in 18½ in 30 in 15 280 psi 32,580 lbf 1000-29 [61][8][62][63]
9351 WSR Mogul WSR 2004 2-6-0 7 ft / 7 ft 9 in 3 ft 2 in 5 ft 8 in 18 in 30 in 2 200 psi 24,300 lbf 9351 [64]

List of boilers

The history of GWR boilers is long and complex. This table lists only the principal dimensions of the boilers (including proposed boilers) mentioned in the table of standard classes.

Selected GWR boilers[5]
Boiler numberLengthFirebox lengthRear diameterFront diameter
Prop 115 ft9 ft5 ft
Prop 211 ft 2 in8 ft 8 in5 ft
114 ft 10 in9 ft5 ft 6 in4 ft 11 in
211 ft7 ft5 ft4 ft 5 in
411 ft7 ft5 ft 6 in4 ft 11 in
510 ft 6 in5 ft 10 in4 ft 9 in4 ft 2 in
714 ft 10 in10 ft6 ft5 ft 6 in
1412 ft 6 in8 ft 8 in5 ft 3 in4 ft 8 in
1512 ft 7 in9 ft 9 in5 ft 8 in5 ft

Notes
  1. Locomotive Superintendent. The office carried various names, changing to Chief Mechanical Engineer during Churchward's tenure.
  2. Fourteen of the class ran briefly as 4-4-2s to allow comparison with French 4-4-2 compound locomotives[6]
  3. The 2884 class (built by Collett) differed mainly in having greater weight, outside steam pipes, and better cabs, not in the principal dimensions.[11]
  4. The 4575 class (built by Collett) differed only in having increased water capacity, not in the principal dimensions.[22]
  1. Griffiths (1987), pp. 143-5.
  2. Griffiths (1987), pp. 146–147.
  3. Gibson (1984), pp. 70-73.
  4. Haresnape (1976), p. 7.
  5. Griffiths (1987), p. 147.
  6. Haresnape (1976), p. 27.
  7. Haresnape (1976), p. 24.
  8. Griffiths (1987), p. 151.
  9. GWREngines (1946), p. 40.
  10. Whitehurst (1973), p. 129.
  11. Haresnape (1976), p. 38.
  12. Haresnape (1976), p. 34.
  13. GWREngines (1946), p. 62.
  14. Whitehurst (1973), p. 130,140.
  15. Haresnape (1976), p. 42.
  16. Haresnape (1976), p. 56.
  17. GWREngines (1928), p. 26.
  18. Haresnape (1976), p. 54.
  19. GWRDrawing4400 (1904).
  20. Haresnape (1976), p. 60.
  21. GWREngines (1928), p. 50.
  22. Haresnape (1976), p. 76.
  23. Haresnape (1976), p. 72.
  24. GWREngines (1946), p. 74.
  25. Whitehurst (1973), p. 137.
  26. Haresnape (1976), p. 45.
  27. GWREngines (1946), p. 70.
  28. Whitehurst (1973), p. 160.
  29. Haresnape (1976), p. 86.
  30. GWREngines (1946), p. 61.
  31. Whitehurst (1973), p. 134,133.
  32. Haresnape (1976), p. 94.
  33. Haresnape (1976), p. 96.
  34. GWREngines (1946), p. 63.
  35. Whitehurst (1973), p. 138.
  36. Haresnape (1976), p. 82.
  37. GWREngines (1946), p. 72.
  38. Whitehurst (1973), p. 162.
  39. Haresnape (1978), p. 30.
  40. GWREngines (1946), p. 42.
  41. Whitehurst (1973), p. 144.
  42. Haresnape (1976), p. 47.
  43. GWREngines (1946), p. 71.
  44. Whitehurst (1973), p. 148.
  45. Haresnape (1976), p. 49.
  46. Whitehurst (1973), p. 136.
  47. Haresnape (1978), p. 78.
  48. GWREngines (1946), p. 73.
  49. Haresnape (1978), p. 84.
  50. GWREngines (1946), p. 46.
  51. Whitehurst (1973), p. 132.
  52. Haresnape (1978), p. 88.
  53. GWREngines (1946), p. 48.
  54. Whitehurst (1973), p. 128.
  55. Haresnape (1976), p. 52.
  56. Whitehurst (1973), p. 147.
  57. Whitehurst (1973), p. 135.
  58. Holcroft (1957), p. 157.
  59. Haresnape (1978), p. 93.
  60. Whitehurst (1973), p. 131.
  61. Haresnape (1978), p. 98.
  62. GWREngines (1946), p. 50.
  63. Whitehurst (1973), p. 124.
  64. WSRMogul (2021).

References
  • Gibson, John C. (1984). Great Western locomotive design : a critical appreciation. Newton Abbot [Devon]: David & Charles. ISBN 0715386069.
  • "Drawing of 4400 class". The Great Western Archive. Retrieved 2 January 2021.
  • Griffiths, Denis (1987). Locomotive engineers of the GWR. Wellingborough: Stephens. ISBN 0-85059-819-2.
  • G.W.R. engines: names, numbers, types & classes. (Reproduction of 1928 edition). Newton Abbot: David and Charles. 1971. ISBN 0715353675.
  • G.W.R. engines: names, numbers, types & classes. (Reproduction of 1946 edition). Newton Abbot: David and Charles. 1971. ISBN 0715353675.
  • Haresnape, Brian (1976). Churchward locomotives : a pictorial history. London: I. Allan. ISBN 0711006970.
  • Haresnape, Brian (1978). Collett & Hawksworth locomotives : a pictorial history. London: I. Allan. ISBN 0711008698.
  • Holcroft, Harold (1957). An Outline of Great Western Railway Locomotive Practice. London: Locomotive Publishing Co Ltd.
  • "Great Western Railway inspired 2-6-0 9351 class No. 9351". West Somerset Railway. Retrieved 4 January 2021.
  • Whitehurst, Brian (1973). Great Western engines, names, numbers, types, classes: 1940 to preservation. Oxford: Oxford Pub. Co. ISBN 0902888218.
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