The 80 Class is a type of diesel electric multiple unit formerly used by Northern Ireland Railways. They were affectionately nicknamed 'Thumpers' by rail enthusiasts due to the thumping noise their engines produced. History By the early 1970s, the MEDs and units inherited from the Great Northern Railway (GNR) had been in service for 20 years, and the MPDs for 10 years. To replace these increasingly life-expired units, Northern Ireland Railways (NIR) placed an order with British Rail Engineering Limited (BREL) for 9 new DMUs. These were to be built as four 3-car and five 2-car sets and were delivered in 1974/75. Structurally, the new trains were based on the British Rail Mark 2b bodyshell, which NIR was already using for the Enterprise service. The new trains were classified as the 80 Class. The power cars were fitted with an English Electric 560 hp diesel engine, with electric transmission to two traction motors mounted on the rear bogie. The seating capacity of the power cars was 45, however after providing for wheelchair accommodation, this was reduced to 42. The vehicle also incorporated a guards/parcel compartment. The intermediate coaches were fitted with an additional door on each side to aid passenger flow and had a capacity of 87. The driving trailers had a small cab built at one end, which necessitated the removal of six seats. This cab was set to the left to preserve the gangway connection, so that two train sets could be coupled together and still allow passengers to travel between the trains. All three types are of integral construction, however the power cars, because of their weight, also have an underframe. They were similar to the UTA 70 Class, both mechanically and electrically. The 80 Class was intended to replace the aging MED, MPD and ex-GNR AEC and BUT railcars on the NCC services and the suburban service between Bangor and Portadown. The railcars proved so successful that a second series was ordered in 1975, entering service in 1977/78. Each vehicle was numbered individually, with power car numbers running from 67 to 69, and 81 to 99. The Intermediate Trailers were numbered 761 to 780 and the Driving Trailers were numbered 731 to 756. Power cars 81 to 89 were built between 1974/1975, while 67 to 69 and 90 to 99 were built between 1978/1979. Intermediate Trailers 761 to 764 were also built between 1974/1975, with 765