In 2009, CAF signed a contract with Translink, owner of Northern Ireland Railways, for the supply of 20 diesel trains, each with 3 cars. These Class 4000 cars were adapted to the new European emissions standards, reducing the consumption and costs of maintenance, all contributing to the procurement of a more ecological train.
A contract was entered into in 2018 to extend the fleet, with 21 new intermediate cars which are fully compatible with the NIR 4000 series units. The new vehicles provide almost 1,400 addition places, thereby increasing capacity and addressing the increasing amount of passengers who use the Northern Ireland railway service.