Deltic (English Electric 3,300hp Diesel-Electric)

Deltic was built by English Electric as a private venture and remained privately owned even though it ran on British Railways metals for 6 years. It was built to prove the Napier Deltic engine for rail use [1]. It was hoped the innovative opposed-piston diesel engine with a much greater power to weight ratio than conventional engines would create a powerful express passenger locomotive that was not as heavy as the likes of contemporary large diesel locomotives. Deltic weighed 106 tons by comparison the Class 44 weighed in at 133tons and had 1,000 less horsepower to play with!

Number built: 1
Built: 1955
Builder: English Electric
Engine: 2 Napier Deltic D18-25 diesels
Power: 3, 300 hp (2, 460 kW)
Wheel arrangement: Co-Co

Deltic was designed with the export market as well as home in mind and was given a "North American" appearance complete with large headlight and speed whiskers. When it was built Deltic was the most powerful diesel-electric locomotive in the world and it showed its performance on the London Midland and Eastern Regions [2] though had trouble with its loading gauge on parts of the East Coast Main Line. In the end the Deltic was ordered for production for the ECML in the form of the rather more British looking (and slightly slimmer) Class 55.

Deltic itself was preserved, being withdrawn from service in 1961. It was first displayed at London's Science Museum before moving to NRM Shildon in the last few years.
Deltic now resides at NRM Shildon

Deltic remained privately owned and never had a BR running number 
Note the large headlight and US appearance

[1] Brian Haresnape, Early Protoype & Pilot Scheme Diesel-Electrics (Ian Allan, 1984) p. 29
[2] John Vaughan, Diesels on the Eastern (Ian Allan, 1983) p. 32