Network rail has admitted health and safety failings over the Potters Bar crash, in which seven people died.
The company will plead guilty to charges which were brought over the condition of tracks near the Hertfordshire station. Six passengers and a pedestrian were killed when a train from London to King's Lynn derailed on 10 May 2002. An inquest last year concluded that a points failure was to blame.
The company will be sentenced next month after Peter Palfrey, chair of the bench at Watford Magistrates Court, said the case was too serious for punishment to be dealt with there.
The Office of Rail Regulation (ORR) launched proceedings last year, after an inquest alleged that there had been breaches of health and safety law. At the time, the overall responsibility for the track rested with Railtrack.
A Network Rail spokeswoman said the firm was pleading guilty because it had assumed all of Railtrack's responsibilities and liabilities. She said that travelling by train was now safer than ever: "The railway today is almost unrecognisable since the days of Railtrack and the Potters Bar tragedy.
"All of the recommendations made by both the industry's own formal inquiry and the health and safety investigation have been carried out."
Six passengers – Austen Kark, Emma Knights, Alexander Ogunwusi, Jonael Schickler, Chia Hsin Lin and Chia Chin Wu – were killed in the crash.
The seventh victim, Agnes Quinlivan, was walking nearby and died after she was hit by debris. More than 70 people were injured.
Louise Christian, a solicitor for some of the victims' families, said there was anger the process had taken so long. "What still worries them is whether the safety concerns have been properly addressed for the future," she said. "This is now a prosecution that can only result in a fine. There's a query whether that will bring about any real accountability, given that Network Rail is a not-for-profit company."
The ORR said it was considering whether it was in the public interest to continue prosecutions against Jarvis, the firm that was responsible for the tracks at Potters Bar. There will be another hearing on 21 March.