to 773 being completed between 1978/1979. Likewise, the Driving Trailers were also completed in batches, with 731 to 739 built between 1974/1975 and 740 to 751 built between 1978/1979. The additional coaches were conversions from BR or old NI Railways loco-hauled coaches, and were not original 80 Class vehicles. These were Driving Trailers 752 to 756 and Intermediate Trailers 774 to 780. During the mid-1990s the surviving vehicles were all renumbered by Translink, by adding 8000 to their numbers to avoid duplication with the bus fleet operated by Ulsterbus and Citybus, also Translink subsidiaries. Use by Iarnród Éireann Three 3-car sets were leased by Iarnród Éireann (IÉ) from NIR in October 1987 for use on, respectively, the Bray–Greystones shuttle (previously operated by a push–pull set rebuilt from CIÉ 2600 Class railcars), the Dublin Connolly–Maynooth route, and the Cork–Cobh line. They were originally intended as a short-term measure until Mark 3 push–pull sets became available. The sets entered service on 2 November. In addition to their regular services, they were employed on a variety of other workings, including a nine-car All-Ireland hurling special from Cork to Dublin. However, although the sets were fitted with Continuous Automatic Warning System and IÉ train radio in March 1990 and "for a while it appeared as if the units were going to be purchased by [IÉ]," NIR required them back when the lease expired at the end of October 1990. A brief "stay of execution" for the Greystones shuttle lasted until 26 November. Refurbishment Despite the increasing age and obsolescence of the 80 Class, the lack of available rolling stock meant that NIR was forced to retain a number of units, even in spite of the entry into service of the new Class 3000. Until 2011, NIR maintained up to three 4-car units for use on passenger services. These saw a pair of 2-car units, a power car and driving trailer, coupled back to back. Six trailers were refurbished and fitted with central door locking enabling them to remain in service until the new Class 4000 units entered service in 2012. (742 had been nominated for retention but was scrapped in May 2008 and replaced in the programme by 752) The power cars were overhauled at LH services in Staffordshire and the trailers at York Road works in Belfast. Set 89-733-738-69 remained in service until 24 May 2008. Set 93-754-749-94 was sporadically on test from