BBC/SCREENGRAB
Passengers aboard two trains that collided near Bedford on Friday afternoon have told the BBC of the panic and injuries they witnessed in the aftermath of the crash.
One person, a train driver, died and 89 others were injured to varying degrees, officials say.
The East of England Ambulance Service said 11 people had suffered "very serious" injuries, and a further 22 had been seriously injured.
"There was a woman in front of me that had completely snapped her leg, and there was a woman behind her - they were sort of on top of each other, she couldn't move because of her back," passenger Brett Byatt told the BBC.
"There was a guy further down the carriage that couldn't move his neck, he was laid on the floor and people were holding him still."
Passengers say one of the trains had stopped on the tracks just south of Bedford when the second crashed into it at around 17:15.
"[We] felt the train brake really hard which seemed odd," said Simon Bentley, who had been travelling from Kettering to London with his wife.
Brett Byatt, a teacher from Bedford, said: "I knew something was up because the train never slows down from Bedford to Luton - and I felt it brake."
East Midlands Railway (EMR) has confirmed that the 16:40 from Corby and the 15:50 from Nottingham - both of which had been travelling to London St Pancras - had been involved in the collision.
Teresa Itabor, from Northamptonshire, had got on one of the trains at 16:57 at Wellingborough on her way to celebrate her birthday in the capital.
"We left Bedford station and there was a massive bang... I didn't know what was going on. My head hit the seat in front of me," she said.
"I opened my eyes and that's when I saw people on the floor with blood everywhere."
Other passengers described similar scenes in the moments after the two trains collided.
"I saw all of the chairs everywhere. It felt like I'd been in a bomb explosion," Dr Peter Knapp told the BBC.
"When I got up, I saw people's bloodied faces and people's legs looked broken and there was smoke everywhere."
Shola Mene said the moment of impact was "like a big bang".
"People flew from their seats... and then someone just flew across and hit my husband in the face."
"There was a lot of blood," she said. "A lot of people had facial injuries."
The crash sparked a massive emergency response, with the British Transport Police declaring a major incident, and fire crews and an air ambulance also attending in a matter of minutes.
Itabor said that, in the immediate aftermath, the doors on her carriage had jammed and would not open.
Paul Calvin, another passenger, said the driver's cab of the train behind was "pretty badly mashed up" and he could see a lot of wounded people walking from the trains, some with "smashed up noses".
Speaking from the side of the road, Knapp said some passengers were "spitting out blood".
Byatt, who was unharmed in the crash, said those in first class had suffered stomach and rib injuries because they had slammed into the tables when the crash happened.
"I'd probably say 90% of the people on my carriage had injuries," he added.
"Everyone else had either a serious wound that was bleeding profusely, or a situation where they couldn't stand, or couldn't move their neck, or I saw a woman's snapped leg."
The authorities are now investigating why the fatal crash occurred - something EMR says it will "make every effort" to help with.
Transport Secretary Heidi Alexander said it was too early to speculate on what that investigation would conclude, while stressing the UK's railways were "some of the safest in the world".
But some of those involved in the collision are already asking what went wrong.
Byatt told BBC Radio 4's Today programme on Saturday morning that, while he had been "shocked" in the immediate aftermath, he was now feeling "pretty angry".
He added: "I don't know at who specifically, but it's more about we've got one of the oldest railway networks and signal failures happen a lot, and now I'm just wondering... why wasn't that signalled to my train and why did that train driver lose his life over this?"
