Back in 1991 43029 was the rear power car on an Intercity service from Newquay to Paddington when the train derailed just after leaving Luxulyan Tunnel. The passengers were sent in groups to 43029 when it operated a free shuttle into Luxulyan station.
On 6th November 2004 it left Paddington trailing 43019 when at 18:12 the train rammed a car at Ufton Nervet and derailed. 43029 suffered very minor damage (mostly to the lower front valancing under the cab, as when it derailed it sank into the ballast). 43019 was damaged severely, becoming the third HST power car to be written off and broken up.
Power cars written off following accident damage:
43173: Ripped open after colliding with a stone train at Southall, used for parts then scrapped
43011: Caught fire after hitting a Thames Turbo at Ladbroke Grove
43019: Took much of the impact at Ufton Nervet and written off.
Information about the Luxulyan derailment sourced from:
http://www.luxsoft.demon.co.uk/village/hst.html