NIR had not procured new rolling stock since 1994, when, in conjunction with Iarnród Éireann, it purchased locomotives and coaches for the Enterprise service.
As part of a major investment programme in the railways in Northern Ireland, NI Railways placed an order totalling £80 million, the largest single investment in rolling stock ever made by NIR, with CAF for 23 3-car DMUs in 2002.
(including 15 on tip-up seats) and have standing room for 280 passengers crush laden.
The first six units (3001-3006) are fitted with CAWS and communication equipment compatible with the rail network in the Republic of Ireland.
Phase 1 of the refurbishment programme was begun during the financial year 2009/10 and cost an estimated £1.2 million.