On this day in 1952, at least 85 people were killed and more than 200 injured in the country's worst peacetime rail crash.
The accident happened at 0820 GMT at Harrow, a north-west suburb of London.
A London-bound express train from Perth ploughed into the back of the 0731 Tring-Euston commuter train as it was about to leave Harrow and Wealdstone station, on the London Midland region line.
Seconds later, a third train coming from Euston crashed into the wreckage.
Survivors described hearing a deafening sound like an explosion and then broken glass and debris flying everywhere.
"It all happened in a second. There was a terrible crash and glass and debris showered on me." said John Bannister, survivor.
John Bannister of Harrow was in the local train in a coach just under the footbridge at the time of the accident, he told the Times newspaper. He added "I blacked out for a moment and when I came round I found I was lying on the line with debris all over me. I managed to free myself and drag myself on to the platform."
There were about 1,000 passengers aboard all three trains, with most casualties at the rear end of the Tring commuter train and the front coaches of the two express trains.
Some of the victims were on the platform as carriages full of commuters were hurled onto them. Others were killed on a footbridge over the track that was punctured by a pile of coaches 30 foot (9 mts) high.
Rescue workers battled to free survivors trapped in carriages at the bottom of the pile. Other coaches were cut through to bring out survivors and the dead. Police officers occasionally shouted or blew their whistles for silence to listen for any sign of survivors.
The Queen and the Prime Minister, Winston Churchill, sent messages of sympathy to the victims and the bereaved.
A total of 108 passengers and four rail crew were killed and nearly 340 people injured. It emerged that the driver of the 2015 sleeper train from Perth had passed two signals at danger when it ran into the Tring-Euston commuter at about 60mph.
To watch the rescue operations and hear witness accounts. click on the following video link: