of two refurbished 3Cig units, nos. 1497 and 1498. The two units were launched into service on 12 May 2005 having been repainted into heritage liveries, 1497 in blue and grey and 1498 in the green that the units carried when built. However, in May 2010, the new timetable changes saw the units replaced for more modern stock to save maintenance on a non-standard fleet of two units. As stated in the relevant timetable, "The slam door trains will be remembered with affection as they pass into history." The change took place on 22 May 2010 and the units have been replaced by a Class 158 on weekdays and a Class 450 Desiro at weekends. The class 421s have both been preserved due to historic significance. Accidents and incidents On 15 December 1971, a Cardiff to Portsmouth Harbour train hauled by Hymek diesel no. D7013 collided with unit 7303 on the high level section of Portsmouth and Southsea station, Hampshire. Sixteen passengers and railway staff were injured In summer 1974 (date unknown) unit 7346 ran away at Wimbledon Park and hit a flyover causing extensive damage to the cab of vehicle 76620. On 26 January 1985, unit 7395 formed a train with 4VEP units 7754 and 7703 which was halted by a landslip near Popham, Hampshire and was run into by Class 33 locomotive 33 104 due to the train crew failing to protect the stranded train. Twelve people were injured and the Class 33 was written off. On 6 November 1985, unit 7390 collided with 4VEP unit 7724 at Copyhold Junction, near , West Sussex due to poor rail conditions and a loss of braking. Forty people were injured. On 4 March 1989, unit Nos. 1280 and 1295 formed a passenger train that overran a signal and collided with another passenger train formed of 4VEP unit 3441 at , Surrey. Five people were killed, 8 were injured. On 6 April 1989, unit 1822 was derailed at whilst working a to service. There were no injuries. On 1 August 1990, Class 119 diesel multiple unit L576 collided with a passenger train comprising 4VEP units 3508 & 3504, and 4CIG unit 1304 at due to overrunning signals. Forty people were injured. On 29 August 1990, unit 1221 was derailed at Ash Vale Junction whilst operating a to service. Further use Following withdrawal from normal service several vehicles have seen further use