The British Rail Class 55 is a class of
diesel locomotive built in 1961 and 1962 by
English Electric. They were designed for the high-speed express passenger services on the
East Coast Main Line between and
Edinburgh. They gained the name "Deltic" from the prototype locomotive,
British Railways DP1 DELTIC (the running number DP1 was never carried), which in turn was named after its
Napier Deltic power units. Twenty-two locomotives were built, which dominated express passenger services on the East Coast Main Line (ECML), particularly London – and London – Edinburgh services, until 1978 when
InterCity 125 'High Speed Trains' were introduced. 1978–81 saw them gradually relegated to semi-fast or newspaper–parcel–sleeper services along the ECML (destinations including , , ,
Hull, and ) plus occasional forays 'offline' – -
Liverpool Lime Street semi-fast and Edinburgh - via stoppers. The fleet was withdrawn from service between January 1980 and December 1981. Three locomotives were retained until 2 January 1982, to work the farewell special, all being withdrawn immediately afterwards, on arrival back at
York. Six locomotives entered preservation during 1982 and 1983, one by the
National Railway Museum, two by the
Deltic Preservation Society, two by the
Deltic 9000 Fund and one privately owned. Two cabs were also privately purchased.