CIÉ 001 Class

The Córas Iompair Éireann 001 Class locomotive was manufactured by Metropolitan-Vickers at their Dukinfield Works in Manchester. The 001 Class locomotive was the backbone of mainline passenger and freight train services on the Irish railway network for forty years from 1955 until the mid-1990s when they were replaced by the new 201 Class.

Viewing dieselisation as a way of bringing operations into profitability, CIÉ placed an order for 94 diesel locomotives to be built by a British consortium on 5 May 1954: sixty being the 'A' class (later 001 Class), and the remainder being smaller 'C' class locomotives for branch line work. With components from Metropolitan Cammell, the English Steel Corporation, Crossley Brothers and Metropolitan-Vickers, the first unit would be delivered to Inchicore in July 1954.

The first of the class to enter service was A3, which entered service on 27 September 1955. The Crossley engines soon proved to be unreliable, and CIÉ would seek to replace them with engines from the Electro-Motive Division of General Motors. GM reluctantly agreed to supply 2 engines as a trial in 1967.

Trials over 1968 would prove to be a success and the entire class would be re-engined over the following years. Relegated to secondary duties after the introduction of the 071 Class, the class would be withdrawn following the delivery of the 201 Class, with the last unit withdrawn on 5 April 1995, and a 'farewell' railtour hauled by 039 occurring on 23 September 1995.

Initially they were fitted with eight-cylinder two-stroke, port-controlled Crossley engines. These were a loop scavenge type, which utilised a patented principle that recycled the normally wasted exhaust-pressure pulse to boost charge air in the cylinder. They produced 890 kW (1,200 hp) at 625 rpm and could do 120 km/h (75 mph). The original sandboxes, which were used to improve traction with the rail, were removed after a few years.

Their Crossley engines proved to be notoriously unreliable from the start. Amongst a plethora of problems were:

There were also problems with generator and motor flashovers.

Similar problems were also encountered on the Crossley-engined Western Australian Government Railways X Class and British Rail Class 28 locomotives.