Factfile: BR Class 55 ‘Deltic’

English Electric built a striking diesel prototype, named Deltic, in 1955, equipped with a pair of lightweight Napier powerplants, of a design originally created for navy gunboats. The engines featured a triangular, opposed cylinder arrangement, hence the ‘Deltic’ name, which was derived from the Greek letter Delta. Detailed 2 trials of the Preston-built prototype were undertaken on British Railways’ West Coast route and, although the London Midland Region eventually deemed the prototype unsuitable, staff on the Eastern Region had other ideas. Unimpressed by the new Type 4 1-Co-co-1s (later Class 40), the Eastern Region requested its own trials with Deltic, which ultimately led to an order for 22 production series locomotives being ordered by BR in 1959. Built at Vulcan Foundry, Newton-le-willows, the production ‘Deltics’ entered service in 3 1961-62 and, with the improved Napier power units capable of generating 1,650hp each, the twin-engine locomotives transformed express train travel on the East Coast Main Line, offering sustained 100mph running. Although not without their technical problems, the ‘Deltics’ proved successful and became extremely popular with enthusiasts, as their supreme performance and characteristic drone marked them out from the diesel crowd. The arrival of BR’S High Speed Train (HST) in the late 1970s spelled the end for the ‘Deltics’, which had become Class 55 under the TOPS system. The Napier engines required regular, expensive servicing and, despite ‘Deltics’ finding new work on secondary ECML and trans-pennine services, the entire class had been withdrawn by January 1982. Six examples have been preserved.

COLOUR RAIL 1: D9018 Ballymoss carries the famous 1A35 headcode, denoting the southbound ‘Flying Scotsman’. The ‘Deltic’ was just a year old when this view was captured, near Thirsk, in the summer of 1962.

COLOUR RAIL 2: In June 1977, 55001 St Paddy waits at the ‘country’ end of the King’s Cross platforms. By this time, the headcode panels and cabside quarterlights have been plated over. The air horns have also been placed atop the bonnets.

Accurascale Class 55 ‘Deltic’ – in detail

COLOUR RAIL 3: Three ‘Deltics’ and a ‘31’ rest at Finsbury Park in April 1981, headed by 55012 Crepello, which was withdrawn the following month. The white cab surrounds became a Finsbury Park trademark during the late 1970s.