Diesel locomotives of Ireland

Although prototype diesel locomotives ran in Britain before World War II, the railways of both the Republic and Northern Ireland changed over much more rapidly from steam to diesel traction, in the 1950s than those in Britain, due to the island's limited coal reserves and (in the Republic) ageing steam locomotive fleet. The initial diesel locomotives for CIÉ were built and supplied by British railway locomotive builders (Birmingham RCW with Sulzer engines and AEI Metropolitan Vickers with Crossley engines), with notably poor results from the latter. From the early 1960s, locomotives with more reliable engines from General Motors Electro-Motive Division (now the independent company, EMD), of the USA, were adopted. In the late 1960s the Crossley engines were replaced by EMD 645 units in a major programme to re-engine the fleet. Since the early 1960s all new locomotives on the two Irish rail systems have been purchased from EMD, with the exception of three from Hunslet Engine Company of Leeds, England, for NIR in 1970.

In 1948, CIÉ commissioned a report from Sir James Milne (General Manager of the British Great Western Railway) on the problems of upgrading its rail services. Despite his recommendation to continue with steam traction, CIÉ decided to push for the complete dieselisation of its railway system, expecting substantial economies of scale.

The first of the two mainline diesel locomotives built by CIÉ at Inchicore Works, each with a Sulzer engine built by Vickers Armstrong, Class 113, entered service in April 1950, following completion of trials.

Subsequently, CIÉ placed one of the largest orders of its time, for 94 locomotives (60 Metro-Vick Class 001, or A Class, and 34 201 Class, or C Class locomotives) with a consortium of four British companies:

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