G&SWR 11 Class
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The G&SWR No 11 was one of the first four-cylinder steam locomotives in the UK. It was built to the design of James Manson at the G&SWR's Kilmarnock Works in 1897,[2][3][6] as a development of his two-cylinder 'Manson Bogies' of 1892.[3][7]
Design
[edit]
This was one of three designs of the first four-cylinder locomotives, produced near-simultaneously around 1897.[3] The others were Webb's Black Prince or Jubilee class and Drummond's T7. As was the typical express passenger locomotive pattern of the day, all were of 4-4-0 arrangement.[i]
The 4-4-0 had been in use for some time before this. The first example of a comparable UK design was the NBR 224 class of 1871. Coincidentally, the first of that class was rebuilt in 1885, after its loss in the Tay Bridge Disaster, to become the first four-cylinder locomotive, although as a tandem compound.[3]
Manson's earlier 'Manson Bogies' were already in successful service. To improve their running at speed, he planned to make a four-cylinder version, which could be better balanced. Inside and outside cylinders ran at 180° to each other, with each side quartered at 90°, as conventional. He may also have been considering a four-cylinder compound, as for Webb.[8] The two inside cylinders shrank in diameter from 18¼ in to 14½, but kept their same 26 inch stroke. Outside cylinders were added of 12½ inches in diameter and 24 inch stroke. Unusually their stroke was shorter than the inside cylinders. This was a limitation of the bogie wheelbase leaving only a short space for the outside cylinders, which sat between the bogie wheels. Although such a difference was unusual, it does not affect their balance. The overall cylinder volume of the four-cylinder locomotive was the same as the two-cylinder.[ii][3][9]
A single set of Stephenson link valvegear was shared between inside and outside cylinders. The valves of the inside cylinders were driven directly, the outside valves were balanced valves mounted above their cylinders and driven through a transverse rocking shaft.[3] Both used slide valves, the inside slide valves mounted between the cylinders, the outside valves placed on top above the footplate.
Service
[edit]It entered service on 13 April 1897[3] and worked express trains between Carlisle and Glasgow, and performed considerable service, its mileage up to the end of the first year being 24,575 miles.[3]
1922 rebuild
[edit]
Given the additional cylinders compared to the 8 class, and the size of their boilers, it was unsurprising that the locomotive had always run better than it steamed.[8] R. H. Whitelegg had already rebuilt the Manson Bogies with a new boiler and simplification to their valve gear, but this boiler was only a little bigger, although simpler to construct, and the need to 'force' the boilers in service increased coal consumption.[10]
In 1922, Whitelegg rebuilt 11 with a larger boiler, the number 394 and the name Lord Glenarthur, after Sir Matthew Arthur, First Baron Glenarthur (1852–1928), then chairman of the G&SWR.
The motion was only slightly changed, with all four cylinders rebuilt to the same 14" diameter, but retaining their same space-constrained differences in stroke.[11] Whitelegg's new boiler also added a small superheater, enlarged the firebox and grate areas, and raised the boiler pressure to 180 psi.[11][12][13][14][15]
References
[edit]
- ^ Although Drummond's T7 had a divided-drive arrangement, where pairs of cylinders drive each axle and there are no coupling rods between them, making it a 4-2-2-0. The T7 had a long firebox, placed between the driven axles, giving it an unusually long coupled wheelbase; there were concerns over the rigidity of coupling rods this long.
- ^ 13,602 vs 14,477 cu. in.
- ^ Ahrons (1927), p. 302.
- ^ a b "Another British Four-Cylinder Engine". Railroad Gazette. Vol. XXIX, no. 34. 20 August 1897. p. 593.
- ^ a b c d e f g h i Bird, George Frederick (January 1899). "British Four-Cylinder Locomotives". Cassier's Magazine. Vol. XV, no. 3. pp. 142–153.
- ^ "Class 11". Locobase.
- ^ "Glasgow & South-Western Four-Cylinder Simple Engine". Railroad Gazette. Vol. XXX, no. 2. 14 January 1898. p. 21.
- ^ Bird, George Frederick (May 1898). "A Four-Cylinder Locomotive". Cassier's Magazine. Vol. XIV, no. 1. p. 93.
- ^ "Manson Bogie". Locobase.
- ^ a b John Speller. "Manson 4-4-0 No. 11". Archived from the original on 18 July 2014.
- ^ Ahrons (1927), pp. 301–302.
- ^ "Class 8/375". Locobase.
- ^ a b Ahrons (1927), pp. 301, 355–356, 359.
- ^ "Class Lord Glenarthur". Locobase.
- ^ "Reconstructed Four-Cylinder Express Locomotive-London, Midland and Scottish Railway (G&SW Ry Division)". Locomotive Magazine. Vol. XXIX, no. 366. 15 February 1923. p. 52.
- ^ Poultney, Edward Cecil (1952). British Express Locomotive Development. London: George Allen and Unwin. pp. 36, 39.
- ^ Casserley, H.C.; Johnston, S.W. (1966). Locomotives at the Grouping, No.3, London Midland and Scottish. Ian Allan.
Bibliography
[edit]- Ahrons, E.L. (1927). The British Steam Railway Locomotive 1825-1925. Amen Corner, London: Locomotive Publishing Co. OCLC 2329259. OL 6715902M.
- Baxter, Bertram (1984). Baxter, David (ed.). British Locomotive Catalogue 1825–1923, Volume 4: Scottish and remaining English Companies in the LMS Group. Ashbourne, Derbyshire: Moorland Publishing Company.
- Smith, David L. (1976). Locomotives of the Glasgow & South Western Railway. David & Charles. ISBN 978-0715369609.