Port Talbot train deaths: Separate investigations launched
Specialists have been drafted in from across the UK to investigate the death of two rail workers hit by a train.
British Transport Police has launched a "thorough and painstaking" probe, while Network Rail is also investigating.
Gareth Delbridge, 64, from Kenfig Hill, and Michael "Spike" Lewis, 58, from North Cornelly, were hit by the Swansea to Paddington train near Margam at about 10:00 BST on Wednesday.
Police said they may have not heard it as they were wearing ear defenders.
The Rail Accident Investigation Branch (RAIB) has also launched an independent inquiry.
British Transport Police (BTP) said it was "highly likely" its investigation would "continue for some time".
Divisional commander for Wales, Supt Andy Morgan, said: "We have drafted in specialist teams from across the UK to assist our local investigators in their efforts.
"We are also very mindful of the impact this incident has created on the community.
"But please be reassured that if any safety-critical matters come to light at any stage, then they will be highlighted to the appropriate agency and acted on urgently."
Network Rail has appointed an independent investigator to form part of an inquiry team that will include trade unions and industry partners.
Chief executive Andrew Haines said many in the company were "still reeling from the shock of the tragedy".
"They were extremely well respected and experienced members of the Port Talbot track team - together they have given over 84 years' service to the railway and they will be missed," he said.
"This is a heart-breaking reminder of how dangerous it can be to work on the railway and highlights to us all the importance of challenging anything that seems unsafe."
A third worker was treated at the scene for shock after the train struck Mr Delbridge and Mr Lewis, but was not injured.
Mr Delbridge's family said he was the "most loving husband, father, brother and granddad".
"He loved life, work and his holidays - but most of all, his family," they added.
"We are devastated to have lost Gaz in such tragic circumstances, and both he and Spike will be missed so sadly by all of their family and friends."
The family of Mr Lewis said he was "loved by everyone".
They said: "We would like to thank everyone so much for their support during this difficult time and ask that we are now given the space we need to grieve."
Alan Gitsham, a former railway worker who used to work with both men, said: "Mike was great, a tidy fella. I'm devastated, I can't believe he's gone."
Kenfig Hill Rugby Football Club said Mr Delbridge was a long-standing member.
Gary Chappell, the club's treasurer, said Mr Delbridge's death was "more than devastating".
"He was an absolutely fantastic guy. He always had a smile on his face," he said.
"He always had time to say hello to you."