An inquest has opened into the deaths of two railway workers killed on a railway track in Port Talbot.
Michael Lewis and Gareth Delbridge died while they were working on the tracks between Port Talbot and Bridgend on 3 July.
A third person was treated for shock at the scene but was not injured.
The hearing in Swansea was told there are three parallel investigations into how the London-bound train struck the two men on the line.
Network Rail is facing demands for answers after their deaths and Transport Secretary Chris Grayling has said there will be a full investigation.
The Coroner, Colin Phillips, said the process of finding out what exactly had happened could take twelve months, and the cause of death had yet to be established.
He said he would review the position in six months.
The families of the two men, aged 58 and 64, were not in court.
Network Rail Wales route director Bill Kelly said the railway network owner was “shocked and distressed” by the “dreadful accident”, and added that it was “fully co-operating” with investigators.
The incident resulted in cancelled trains, with replacement buses being put on for rail passengers.