43021 was delivered into service on 9 July 1976 and 43132 on 21 July 1979. Operational life was extended by Brush Traction when MTU power units were fitted, 43021 being fitted between 9 October 2006 and 21 December 2006, with 43132 going into Brush's Works between 18 July 2007 and 20 September 2007. On 31 August 2017 both units were taken off lease from First Great Western to be transferred to ScotRail, running as a 2+4 set to Craigentinny on September 1st, along with Mk.3 coaches 40207, 42047, 42207 and 44015, where they were rebranded with vinyls proclaiming 'A New Era' on the power cars and 'We're building the best railway Scotland's ever had' on the central two coaches.