In the mid-1980s, Northern Ireland Railways was in the process of upgrading its rolling stock. Having already purchased three
new locomotives, it then proceeded to purchase replacements for its
70 Class diesel multiple units. A total of nine three-car trains were constructed by
British Rail Engineering Limited between 1985 and 1987, intended to supplement the existing
80 Class DMUs then in service. The trains were constructed using underframes of existing
Mark 1 coaching stock, altered to using gauge and new
Mark 3 bodyshells with powered sliding doors. Because of this, they bore a strong resemblance to the
British Rail Class 150,
British Rail Class 210,
British Rail Class 317,
British Rail Class 318 (especially prior to its refurbishment) and
British Rail Class 455, as they also use the Mark 3 bodyshells with end doors. These were combined with refurbished power units and traction motors from the withdrawn 70 Class units (there were only eight 70 Class units available to be salvaged, so the equipment for the ninth train came from a withdrawn Class 80 train, powercar 88 that was damaged at a collision at Hilden). The power cars of the 450 Class units were named after various Northern Irish castles. They entered service in a cream, orange, and red livery, before adopting the blue and silver livery later. On Thursday 9 March 1995, a 450 Class train was used to form a royal train when Queen Elizabeth II officially opened the
Dargan Bridge, composed of two cars from 455 coupled to two cars from 459. The 450 Class operated on the same principle as the prototype
Class 210 DMUs on the
British network, in that they consisted of a single power car containing the traction and generating equipment (numbered 45x), an intermediate trailer car (numbered 79x) and a driving trailer (numbered 78x) as permanently formed 3 car sets. An additional "8" was added to the start of all the cars so that they could be used by
Translink's computer system. In 2005, the entire fleet underwent an extensive refurbishment to bring them up to a similar standard to the newly introduced
3000 Class units, enabling them to remain in service for at least another 5 to 7 years. This took them up to the point where they became "life-expired." In 2011, the entire 450 Class fleet, together with the remaining
80 Class units, was listed by NI Railways for disposal. The first of the trains was broken up and scrapped in April 2012.
Current status The entire 450 Class fleet was withdrawn from service in 2012, following the arrival of enough
4000 Class units to displace the 450 units serving the
Larne Line and
Portrush branch. Eight out of the nine units have been cut up for scrap. The sole remaining example has been purchased for preservation by the
Downpatrick and County Down Railway. ==Operations==