The worker died earlier this month when he was struck by a train at Stoats Nest Junction, between Purley and Coulsdon South stations on the main line from London to Brighton.

He had been contracted to carry out protection duties in connection with engineering work on the railway.

This involved placing red lamps and detonators (explosive audible warning devices) on two tracks.

After completing this duty the victim was walking south along the down slow line when he was struck by a passenger train which had crossed over from the down fast line and was travelling at about 70 mph.

The RAIB’s investigation will identify the sequence of events which led to the accident and will consider:

• the reasons why the member of staff was in the place where he was struck
• the arrangements in place for his protection while he was carrying out his duties
• the risks associated with the protection of engineering work on the line
• any underlying management factors