Region of British Railways in 1955, generally operating fast London to Liverpool freight trains; it was withdrawn and after modifications re-entered services in 1956. Tests were carried out on the Settle to Carlisle line in August/September 1956, after which it operated passenger trains, The Shamrock and The Merseyside Express, between London and Liverpool, followed by London-Carlisle trains, and in 1957, returning to London-Liverpool trains. The region's chief mechanical and electrical engineer, J.F.Harrison, rejected the design, believing high-speed engines (i.e. 1500 rpm) unsuitable for railway applications. In 1957, Gerry Fiennes, the line traffic manager on the former Great Northern route out of London King's Cross station, was seeking high power locomotives to run services on the East Coast Main Line, having found the 2000 hp English Electric type 4 locomotives produced under the 1955 modernisation plan lacking sufficient power for his planned timings; as a consequence he proposed using 'Deltic' type locomotives on the line. Objections to the order included those arising from: a limited permitted top speed due to the mass of the locomotive; the potential for the order to delay a proposed (1957) electrification scheme of the line; as well the size which required modifications to the King's Cross platforms. An order was placed in 1959 for 22 Class 55s to replace 55 steam locomotives. Preservation DP1 was in service until 24 November 1960 when a severe oil leak in one of the engines was discovered. The locomotive was sent to English Electric Company's Works at Newton-le-Willows, Lancashire the next day for repair. However no repairs were sanctioned and the locomotive was withdrawn from service in March 1961 having completed . Plans to test it in Canada fell through, and the locomotive was donated in April 1963 to the Science Museum, South Kensington and placed on public display. After 30 years at the Science Museum, it was transferred to the National Railway Museum, York in October 1993. About 11 years later it was moved north to the National Railway Museum Shildon, County Durham in July 2004. In August 2012 it was loaned to The Ribble Steam Railway in Preston, Lancashire, which is barely a mile away from where it was originally built, returning to Shildon in October 2015 where it remains as of January 2023. Restoring the two Deltic engines installed in DP1 to running condition is not feasible. The engines (Type E158, D18-12) although similar, differ from those