The driver of a train which struck and killed two rail workers sounded the horn when he saw the men in danger, accident investigators have said.
Michael Lewis, 58, and Gareth Delbridge, 64, died while carrying out engineering work for Network Rail near Port Talbot on July 3.
The Rail Accident Investigation Branch (RAIB) said that the train was travelling at around 73mph when it approached the location. The driver saw three workers on the line and responded by sounding the horn and applying the emergency brakes. The train was then travelling at around 50mph.
CCTV images taken from a camera at the front of the train suggest the workers, one of whom survived, did not become aware of the train until it was ''very close to them'', the RAIB said.
The three rail workers were using a tool with a petrol engine, meaning at least one of them was wearing ear defenders.
The RAIB investigation will consider a number of aspects in relation to the accident, including the planning of the work, the protection arrangements in place and what might have influenced the actions of those involved.