Network Rail was fined £4m on Wednesday over safety failures in the lead-up to the fatal Grayrigg train crash.
The firm, responsible for the upkeep of the railways, accepted it was at fault for the derailment which which killed one passenger and left 86 others injured, 28 of them seriously.
Margaret Masson, 84, from Glasgow, died from multiple injuries after a Virgin Pendolino London to Glasgow express train crashed on the West Coast main line near the remote Cumbrian village of Grayrigg on the night of February 23, 2007.
Network Rail Infrastructure Ltd admitted a charge under section 3(1) of the 1974 Health and Safety at Work Act last month and was sentenced at Preston Crown Court today.
Network Rail chief executive Sir David Higgins said: "The Grayrigg derailment in 2007 resulting in the tragic death of
Mrs Masson was a terrible event. Within hours it was clear that the infrastructure was at fault and we accepted responsibility, so it is right that we have been fined.
"Nothing we can say or do will lessen the pain felt by Mrs Masson's family but we will make the railways safer and strive to prevent such an accident ever happening again."
He went on: "We have learnt from the accident, determined to recognise what we got wrong and put it right. An event like this affects everyone in the company, and especially those with responsibility for the track.
"Since the accident, much has changed in the way we plan and carry out maintenance work with new systems put in place to improve the quality and safety of our railway which is why we now have one of the safest passenger railways in Europe."
Ian Prosser, director of railway safety at the Office of Rail Regulation, said: "The derailment near Grayrigg was a devastating and preventable incident which has had long-term consequences for all involved. It tragically caused the death of Mrs Masson, and shattered the lives of others. My thoughts are with Mrs Masson's family and all those injured and affected by this horrific incident.
"Under Sir David Higgins' leadership, Network Rail is focused on driving safety measures and I welcome the company's progress on implementing safety recommendations made after this incident. But the pace of carrying out improvements has, at times, been too slow and the rail regulator has had to repeatedly push the company to bring about change."
Mr Prosser went on: "Britain's railways are safe and are one of the safest in Europe. But there is absolutely no room for complacency.
"Where failings are found those at fault will be held to account and the entire rail industry must continue to strive for improvements to ensure that public safety is never put at a similar risk again."
The court was told the 300-tonne locomotive derailed at 95mph after hitting a badly maintained and faulty set of points, with all nine carriages of the Class 390 tilting train coming off the tracks.
Stretcher bars holding the moveable rails a set distance apart when the points are operated had failed, causing the train's wheels to come off the tracks.
A Rail Accident Investigation Branch (RAIB) report in the aftermath of the crash confirmed the "immediate cause" of the derailment was the poor maintenance of the failed points.
But during the two-week inquest into the death of Mrs Masson held last year, the hearing was told of a catalogue of
problems with maintenance within Network Rail.
The company admitted a charge under section 3(1) of the 1974 Health and Safety at Work Act,
Passing sentence, Mrs Justice Swift said: "This was a very serious offence and could have easily led to greater loss of life than actually occurred."
The judge said if convicted after trial the penalty would have been £6 million but credit was given for the guilty plea.
Network Rail was ordered to pay the sum, along with £118,037 costs, within 28 days.