BBCA passenger has died following a crash involving two trains in mid Wales.
Four other people were seriously injured in the crash and a further eleven required hospital treatment, according to the Rail Accidents Investigations Branch (RAIB), which is looking into the Powys collision.
The man who died was in his 60s and travelling from Shrewsbury.
His cause of death has not been revealed but British Transport Police said at the moment they did not believe it was as a result of injuries sustained in the crash.
The BBC has been told the 18:31 westbound service from Shrewsbury to Aberystwyth continued for about 1,000 metres (3,280ft) beyond where it should have stopped, before hitting a stationary 19:09 train from Machynlleth to Shrewsbury on Monday evening.
The RAIB said an initial inspection found that the train may have entered into wheel slide when braking.
It added that initial evidence suggested that the collision occurred at a speed of approximately 24 km/h (15 mph).
It happened near the village of Llanbrynmair at about 19:30 BST.
British Transport Police said a criminal investigation was not at the moment underway.
The Welsh Ambulance Service said it took seven patients to hospital by ambulance.
Anthony Hurford, a passenger on the Shrewsbury-bound train, said he felt “pretty shell-shocked”.
“The word that keeps coming to my head is just brutal really.
“Just going from, I don’t know how fast we were going, maybe 40, 50, 60mph (64-96km/h) , to nothing in the blink of an eye,” he told BBC Breakfast.
“Somehow my body bent the leg of a table and ripped it off its bolts attached to the wall.
“Suddenly I was on the floor with my laptop strewn ahead of me, wondering what the hell had happened,” he said.
“He [the driver of the other train] tried to stop at the lights. At the top of the hill there’s a signal that I guess would have been a passing place and for whatever reason the train wouldn’t stop.
“There must have been 30/40 people from fire [service]. There was British Transport Police who had come from Birmingham, there were three helicopters, people had come from north and south Wales as far as I’m aware. I was checked by three or four different medics.”
Dan JonesIfan Edwards, a witness who lives near the scene of the crash, said he saw a number of ambulances passing, an air ambulance and two coastguard helicopters.
He said it appeared that one of the trains had failed to stop in the normal place on a hill “and from what we can gather he just slid and he couldn’t stop the train”.
Transport Minister Ken Skates told the Senedd that safety was the Welsh government’s “prime concern”.
Plaid Cymru’s Senedd member for Dwyfor Meirionnydd, Mabon ap Gwynfor, said he had received messages from constituents worried a crash could happen again.
Skates promised lessons would be learned “as soon as possible”.
Network Rail and Transtport for Wales (TfW) said in a joint statement it was a “low-speed collision”.
TfW chief operating officer Jan Chaudhry van der Velde said he could not discuss the causes of the accident but said its rail accident investigation branch arrived at the scene on Monday night and remained there.
A full report would take several months to be processed, he said.
“The line is largely made up of stretches of single line where trains use one line to travel in two directions and where trains need to pass each other, we have passing loops,” he said.
“Where the collision happened there is one of these passing loops,” he added.
Local councillor Elwyn Vaughan said the crash was “a shock and a surprise”.
“It is a single track line, so that’s unusual in many contexts, but there are dedicated passing places,” he said.
“The norm would be one train parks there, and the other passes. The fundamental question is, why that didn’t happen last night?”
He said a new digital system to stop trains might be to blame, or leaves on the line, given the steep incline at the location of the crash.
The Rail Accident Investigation Branch (RAIB) deployed a team of inspectors to the site of the crash and once inspected, decisions will be made on the need for further resources.
Steve Witherden, MP for Montgomeryshire, described it as “tragic”.
“I think the people involved and their families will want answers as soon as possible but I also think it’s important that we don’t speculate and we let the investigation carry out its work,” he said.
The Cambrian railway east of Machynlleth will be closed while investigations continue, Network Rail and Transport for Wales said, urging passengers not to travel on that part of the network.
Witherden said he had heard it could take “several days” before the track was safe to reopen.
Earlier on Monday TfW advised passengers its services were running at reduced speeds through Dovey Junction station – which is on the same line – because previous trains reported the track was “extremely slippery”.
The operator suspended all services on the separate Heart of Wales line on Tuesday “until further notice” due to “poor rail conditions”.
Traffic Wales said the A470 was closed in both directions between Caersws and Glantwymyn, while Transport for Wales said rail replacement services were in operation.
The incident was attended by the ambulance and fire services, local police, and the coastguard, with support from the rail industry, BTP said in a statement.
Residents reported seeing an air ambulance at the scene.
BTP said the family of the man who died had been informed and was being supported by specialist officers.
It also said residents would see an increased police presence in the coming days as officers worked to understand the circumstances leading up to the collision.
Writing on X earlier, Welsh First Minister Eluned Morgan said: “My thoughts are with all those involved in the rail incident in Powys earlier this evening.
“I would like to thank the emergency services for their response and have asked to be kept informed of any developments throughout the night.”
UK government Transport Secretary Louise Haigh said she was “incredibly sorry” to hear about the crash.
“Safety on our railways is my absolute priority and we are working at pace with Transport for Wales and Network Rail to understand what happened and how we can better prevent it going forward.”
