It silently zipped through the pitch black countryside like a ticking time bomb.
Growing faster and faster with each passing second, its approaching danger was oblivious to those in its path.
And at 40mph, it ploughed into a gang of workers on one of the steepest stretches of railway in the country.
The 16-tonne flat wagon, loaded with scrap steel rail, had broken free from its workstation at the top of Shap Fell in Cumbria.
It hurtled down the West Coast Main Line for three and a half miles before violently crashing into ten maintenance men repairing the track at Tebay.
Married father-of-two Chris Waters, 53, of Morecambe, experienced railwayman Colin Buckley, 49, and 30-year-old former postman Darren Burgess, both of Carnforth, were killed.
Their colleague, Gary Tindall, 46, of Tebay, also suffered horrific injuries and died.
The men, working for contractor Carillion, did not stand a chance as the unmanned trailer ran into them without warning on the 1 in 75 gradient slope. Such was its strength, it continued on for another mile before coming to a halt. It was shortly after 6am on Sunday, February 15, 2004.
The accident had also injured five other workers.
Others, like Lancaster man Tom Angus, then 57, helplessly looked on as the trailer barrelled into his friends.
Reliving the horror, Mr Angus, of Scotforth, said: “I was standing in the space between the two tracks and, for some reason, some of us stepped out.
“That is when this black object came past with a ‘ssshhh’ and just ran right over them. I was just two or three feet from it.”
A major emergency operation swung into action with ambulances, fire crews and police racing to the area.
Firefighter Sean Hevey was the first to arrive and could hear mobile phones ringing on the motionless victims.
He said: “I was met with a person covered in blood. He said: ‘Don’t go down there, it’s absolute carnage’. We found a couple of the guys.
“There was nothing we could do for them. There was no one to be released. One or two were walking wounded.”
The injured were rushed to the Royal Lancaster Infirmary.
News of the incident soon reached the media and TV crews and journalists were making their way to the remote hamlet to report on another UK rail tragedy.
As three North Lancashire families mourned their loved ones, there was an urgency to find out exactly what had gone so terribly wrong.
British Transport Police, the Health and Safety Executive and Her Majesty’s Railway Inspectorate launched a joint investigation.
The National Union of Rail, Maritime and Transport Workers (RMT), of which all four victims were members, called for all maintenance to stop until the cause was clear.
Craig Johnston, RMT regional organiser for the north, said: “I got phone calls to say that we’d had a tragedy – that four people had gone to work that night and not gone home to their loved ones.
“My members were there on the scene a short period of time after it happened, saw the immediate aftermath and suffered psychologically.”
Early inquiries into the accident were definitive. The detective who led the investigation recalled: “It was fully established the week after that there was a problem with the brakes on the trailer. The brakes were disabled at several points.”
Mr Johnston added: “There was sadness and then disbelief of how it could occur - and then this over-powering level of anger.”
The funeral of Chris Waters, who lived in Cross Street, Morecambe, with his wife Christine and two children, took place at the town’s Methodist Church on February 26.
Mourners gathered at a ceremony for Colin Buckley, of Hunter Street, Carnforth, just hours later at Lancaster Crematorium.
And Darren Burgess, who lived at Grosvenor Place, Carnforth, was remembered the following day at the town’s Christ Church before a service at Lancaster Crematorium.
Reverend Stephen Jones, Parish Priest at Christ Church, Carnforth, knew Darren Burgess personally.
He said: “The accident had a significant effect on many people in the town, not least among the men’s colleagues on the railway and others who were injured both physically and psychologically.
“There’s quite a comradeship because of the history of the town and its association with the railway and I think that was a source of strength for everybody.
“It was a tragic incident for everybody around here. The mood was solemn.”
Within weeks, a meeting was arranged to discuss how the men should be remembered. It was the start of a fundraising campaign for two memorials at the accident site and Carnforth railway station.
A track-side vigil near the scene of the accident was first organised by the RMT on February 15, 2005.
It has been held every year since and is an important time for the victims’ families and colleagues.
This weekend they will gather again to remember their loved ones on the tenth anniversary of the event which forever changed their lives. The ceremony starts at 12pm and will be followed for the first time this year by a get-together with food and drink at Tebay railway club.
It will be especially poignant for people like Christine Waters, 60, widow of victim Chris. The couple’s two children, Alan and Donna, were 16 and 21 respectively at the time.
Mrs Waters, who still lives in Cross Street, said: “My daughter has a child now. Chris has missed out on that.”