Survivors and bereaved families stood in silence to mark the 10th anniversary of the Paddington rail crash.
They were joined at the crash memorial site in west London by leading figures from the rail industry and the emergency services as well as Transport Secretary Lord Adonis.
Some of the bereaved wept as they stood round the memorial stone at Ladbroke Grove which bears the names of all 31 killed in the crash.
Many laid flowers on the stone which overlooks the crash site.
All were gathered to remember the fateful morning of October 5, 1999 when, at 8.09am, a Thames Trains diesel train leaving Paddington station crashed almost head-on with a London-bound high-speed Great Western train.
To add to the poignancy of the short ceremony, a first Great Western train passed beneath the memorial site on its way into Paddington.
Among those who laid flowers was Denman Groves and his wife Maureen, from Gloucestershire, who lost their daughter Juliette, 25, in the crash.
An accountant from Chiswick, west London, she was travelling on the Thames train which had passed through a red signal after leaving Paddington and crashed into the Great Western train which had departed from Cheltenham Spa station in Gloucestershire.
Lord Adonis said: "Paddington was a terrible tragedy and one of the worst in the world's history. I am glad that lessons were learned from the accident and that railway safety has improved but that does not reduce the nature of the tragedy and the impact it had on so many lives."
Network Rail (NR) chief executive Iain Coucher laid flowers on the memorial stone. He said: "I am here to pay my respects. This was an event that changed the railways. It led to a change in the mindset. You can never do anything other than put safety first."
