A driver said: "I have lost everything... we are off the rails" moments after a train ran over faulty points as it approached a station, an inquest has heard.
Signal inspector Roger Badger, who was travelling in the driver's cab, told the inquest into the Potters Bar rail crash there had been a "violent jolt" as the train approached the station.
Mr Badger was speaking as the inquest - in Letchworth, Hertfordshire - began hearing evidence about the accident on May 10, 2002.
Mr Badger said he had been on the 12.45pm train - which was travelling from King's Cross to King's Lynn, Norfolk - as a "familiarisation" exercise. He said all was normal until the train approached the station at Potters Bar, Hertfordshire, at about 1pm.
"The train jolted. It then paused for a second or so. Then there was another violent jolt," said Mr Badger.
"(The driver) said: 'I have lost everything...' He said: 'We are off the rails'."
Six passengers - Austen Kark, Emma Knights, Jonael Schickler, Alexander Ogunwusi, Chia Hsin Lin and Chia Chin Wu - and pedestrian Agnes Quinlivan died and more than 70 people were hurt as a result of the crash.
Mr Badger said after jolting the train automatically went into "full emergency brake application". He said he walked ahead to warn on-coming trains then saw that the last of the train's four carriages had become detached.
Mr Badger told jurors: "I saw the fourth carriage across the station amongst a tangle of overhead wires."
Judge Michael Findlay Baker QC, sitting as a deputy coroner, has told jurors that the crash was caused by a faulty set of points south of Potters Bar station. He said driver Gordon Gibson could not be blamed.