Thames Trains has been fined a record £2m over the Paddington rail crash in which 31 people died.
Hundreds were injured and 31 died in the crash at Ladbroke Grove
Its train passed a red light in 1999 at Ladbroke Grove in west London colliding with a First Great Western train.
An Old Bailey judge said the firm had not taken an "achievable step" to limit the risk of a crash, by ensuring the driver was properly trained.
The firm had admitted two breaches of health and safety law at London's Bow Street Magistrates Court in January.
On Monday Justice Rodger Bell told the court he was satisfied it was not the case that Thames Trains had put profits before safety.
But he said the company should have been aware there was a problem with the signal at Ladbroke Grove and made "serious omissions" in its driver training.
Handing down the £2m fine - the highest awarded in an HSE case - the judge said he had reduced the fine by a third to take the company's guilty plea into account.
Thames Trains chairman Martin Ballinger accepted the judgement, and admitted the accident was foreseeable and preventable.
"Thames recognises that the value of the fine is irrelevant to the grief and
suffering of the bereaved and injured.
"I share a sense of personal failure with many in the industry.
"No words can adequately express the heartfelt anguish and sorrow felt
throughout Thames Trains for the devastating consequences."
Relatives of those who died in the crash welcomed the decision.
Denman Groves, who lost his daughter Juliet, said: "I think it was a fair
MAJOR DISASTER PAYOUTS
£22.3m - paid out in compensation to victims and their families in the 2001 Selby rail crash
£1.5m - paid out by Great Western Trains Company Ltd following the 1997 Southall rail disaster in west London
£550,000 - to each relative of the 170 victims who died in the 1989 Lockerbie air disaster
After the judgement there were calls for the money to go to survivors, rather than to the Government.
No individual members of Thames Trains were prosecuted by the HSE but the firm could have faced an unlimited fine.
Great Western Trains Company Ltd was fined £1.5m after being prosecuted under the act following the 1997 Southall rail crash in west London in which seven people died.
On Monday, Hugh Carlisle QC, prosecuting, said driver Michael Hodder had not been warned about an "infamous" signal in the Paddington area.
He told Mr Justice Bell: "If he had been properly trained, properly warned, driver Hodder would have paid greater attention to the signal and the collision would have been avoided.
The signal, which was "part of one of the most dangerous combinations of signals in the national rail network", had featured in a Railway Group Safety Performance Report of signals most frequently passed at danger, Mr Carlisle said.
"The collision was on a massive scale with devastating damage causing great loss of life and injury."
Anthony Seys Llewellyn QC, defending Thames Trains, said the company had never tried to avoid its responsibilities in relation to the crash.
"This is a company which had a positive safety
culture and record, and one which had displayed useful innovation in safety matters," he told the judge.