Rail infrastructure company Network Rail (NR) faces a fine when it is sentenced in court tomorrow for safety failings over the 2002 Potters Bar train crash.
NR has admitted breaching health and safety regulations in the May 2002 Hertfordshire disaster, which claimed seven lives.
NR's predecessor company Railtrack was the infrastructure company in charge at the time of the crash but NR has shouldered the responsibility.
NR bosses will learn the size of any fine at St Albans Crown Court in Hertfordshire.
The prosecution, under the Health and Safety at Work Act, has been brought by the Office of Rail Regulation (ORR).
The now-in-administration maintenance company, Jarvis, which was responsible for the section of track at Potters Bar, also faced prosecution but the ORR decided in March not to proceed as the prosecution was "no longer in the public interest".
Six passengers and a pedestrian died, and more than 70 people were injured, when a West Anglia Great Northern express train travelling from London to King's Lynn in Norfolk derailed at a faulty set of points just outside Potters Bar station on May 10 2002.
The train derailed, with part of it getting wedged under the canopy of Potters Bar station.
NR has admitted failings over the installation, maintenance and inspection of adjustable stretcher bars which keep the moveable section of a track at the correct width for train wheels.
The ORR brought the prosecution after the jury at the long-awaited inquest into the crash in July last year found that unsafe points caused the accident.