Lancashire & Yorkshire 4-4-2 Locomotives in Great_Britain

Class Highflyers (Locobase 3023)

Data from C J Bowen Cooke, British Locomotives: Their History, Construction, and Modern Developments (3rd rev and enlarged ed), (London: Whittaker and Co, 1900). See also Edward Cecil Poultney, British Express Locomotive Development (London: George Allen and Unwin, 1952), p. 51-53.

Coming just a year after Ivatt's pioneering Atlantics, these engines, designed by Sir John Aspinall, represented a big jump in size and power. The high-pitched boiler ahead of a Belpaire firebox was the largest then in use in Britain.

Locomotive Superintendent Hoy wrote Bowen Cooke about the design (pp. 266-: "The engines were designed to work the heavy and fast summer traffic, without 'piloting', between Manchester, Blackpool, Southport, Liverpool, Leeds, and York, over gradients of 1 in 63, 1 in 77, etc ...The dimensions represent the extreme limits of height and width available on British railways, as the engine only clears the loading gauge by a very few inches." Indeed, Poultney argues that the very tall drivers contributed to the locomotives' success. "For fast traffic, there is no doubt whatever that slide valve engines required large driving wheels for free running, while, when climbing, the relatively low speeds in revolutions would tend to improve the mean pressure developed in the cylinders for any given cut off."

Aspinall's Atlantics stayed in service long enough to gain a superheater and replace the inside bearings on the trailing axle (which tended to overheat) with outside bearings. The last of these wasn't retired until the early 1930s.

See Ahrons (1927) and Glover (1967).