Network Rail and maintenance company Jarvis Rail are to be prosecuted over the 2002 Potters Bar crash, the Office of Rail Regulation (ORR) has said.
Six people died on a London to King's Lynn train which derailed after a points failure on 10 May 2002. A pedestrian was also killed.
A Health and Safety Executive report said poor maintenance was to blame.
The case - over alleged safety breaches - is due to be heard at Watford Magistrates' Court in January.
In 2005, the Crown Prosecution Service (CPS) said there was no realistic prospect of conviction for gross negligence manslaughter against any individual or corporation in relation to the crash.
The rail regulator said it had been informed last month that the CPS saw no grounds to reconsider its decision.
However, the ORR's director of rail safety Ian Prosser said the recent conclusion of the inquest had paved the way for the prosecution under the Health and Safety at Work Act.
"I have decided there is enough evidence, and it is in the public interest, to prosecute Network Rail and Jarvis Rail for serious health and safety breaches," he said.
"For the sake of the families involved, we will do all we can to ensure the prosecutions proceed as quickly as possible."
At the time of the crash the company in charge of rail infrastructure was Railtrack but its responsibilities were taken over by Network Rail in October 2002.
The ORR said the charge resulted from "failure, as infrastructure controller for the national rail network, to provide and implement suitable and sufficient training, standards, procedures and guidance for the installation, maintenance and inspection of adjustable stretcher bars (part of the points)".
'Safer than ever'
Network Rail said in a statement that the modern railway was "almost unrecognisable since the days of Railtrack and the Potters Bar tragedy of 2002".
It added: "Private contractors are no longer in control of the day-to-day maintenance of the nation's rail infrastructure since NR took this entire operation, involving some 15,000 people, in-house in 2004.
"All of the recommendations made by both the industry's own formal inquiry and the health and safety investigation have been carried out.
"Today the railways are safer than they have ever been, but our task remains to build on that record and always to learn any lessons we can to make it ever safer for passengers and those who work on the railway."
Jarvis Rail, the maintenance contractor for the Potters Bar area at the time of the crash, went into administration in March 2010 but faces a charge under the same section of the act.
Bob Crow, general secretary of the Rail Maritime and Transport union said the news was "better late than never".
He added: "This prosecution also sends out a clear warning to those currently responsible for rail maintenance, and the government, in this climate of cuts to transport budgets that anyone caught playing fast and loose with rail safety can expect to feel the full force of the law."
Gerry Doherty, leader of the TSSA rail union, said: "It is deeply regrettable that it has taken eight long years and much suffering by the families involved to get to this stage.
"It seems at long last we are going to find just who was responsible for this tragedy."