Gareth Delbridge and Michael Lewis could not hear train coming
Two rail workers were killed because a lookout was not in place as they carried out track repairs, a report has found.
Gareth Delbridge, 64, and Michael Lewis, 58, were wearing ear defenders - and could not hear the train coming when they were killed.
An interim report found there was no official lookout in place to guard for oncoming trains as the 70mph locomotive approached.
The joint report by Network Rail and First Great Western said the men were working on the line near Margam, Port Talbot, when Mr Delbridge and Mr Lewis were hit.
The report said a safety officer "calculated that 30 seconds warning time of approaching trains would need to be given by a distant lookout located approximately 640 yards."
It said: "This would allow the team to reach a position of safety before a train travelling at the line speed of 90mph would reach their location.
"One person was identified in the briefing sheet as distant lookout but no distant lookout was deployed."
Mr Delbridge and Mr Lewis, both from the Bridgend area, were killed instantly in July.
The report found there was "no safe system of work in place for those working on the points. Those working on the points were unaware of the approaching train".
It added: "The work group of six became separated into two groups of three staff which compromised the number of lookouts available and therefore any safe systems of work.
"The wide experience of the closely-knit group and familiarity with each other potentially affected their perception of risk."
Network Rail said it continues to investigate the accident on the tracks on July 3.
Martin Frobisher, director of safety said: "The whole railway family shares the loss of Gareth and Spike.
"Nothing will lessen the pain but understanding what went wrong and learning from that will, I hope, go some way to reassure all those affected that we will do all we can to stop it ever happening again.
"Today is the first step in that journey as we share an initial investigation into what happened.
"We will continue for several months to look deeper into the root causes before we make recommendations for our organisation and all of our people for the future."