Network Rail says it will plead guilty to a series of health and safety offences following the fatal Grayrigg train crash in 2007.
Passenger Margaret Masson died and 86 others were injured when a Virgin Pendolino was de-railed in Cumbria.
The company will be sentenced next month.
Today Margaret Masson's son, George, said that his family had been through hell for the last five years.
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Wintry start for some and windy. Brightening later
Emma brings you Saturday's forecast
Longest cold spell of winter so far. Mainly dry and bright, but feeling bitterly cold today. Very wintry further east, blizzards possible