London Underground and its contractors have been fined £300,000 after a maintenance wagon weighing 39-tonnes hurtled out of control through seven tube stations.
London Underground along with Tube Lines Ltd and Schweerbau GMBH pleaded guilty to endangering passengers and staff under Health and Safety law.
During the incident a passenger train that was in front of the maintenance wagon was told to keep going and not stop.
Commuters were reportedly told to run to the front carriages.
A dramatic video of the moment the train careered dangerously out of control along the Northern line shows a panicked worker running along the track beside it, before giving up and placing his head in his hands.
After four miles and 16 minutes the runaway train stopped at Warren Street station when it came to an uphill section of the line.
Judge Richard Hone said: "There was the potential of terrible tragedy."
To those involved it must have seemed an extremely frightening eternity," he added.
The court was told that the fault that led to the incident on Friday, August 13, 2010, had since been remedied and was unlikely to occur again.
"It could have led to tragedy but thanks to the immediate actions of LU staff, no one was hurt," said Mr Ashley-Norman.
The train, which began rolling downhill without brakes from Highgate and into central London, reached speed of 30mph as it raced through stations.
Mr Ashley-Norman said attempts were made to slow the runaway train down using points at Camden Town and Mornington Crescent, and the trains were diverted onto different lines.
It eventually stopped at Warren Street central London when it reached an upward incline.
"In the event, and fortunately, no one was harmed," added Mr Ashley-Norman.
Keith Morton, QC, for the Tube companies, said: "London Underground is one of the safest railways in the world - if not the safest."
He said a billion passenger journeys were made on London's Tube network each year.
Bob Crow, leader of the RMT transport union told the Evening Standard newspaper: "This shocking incident, which could very easily have resulted in a major tragedy and loss of life....should continue to serve as a wake-up call to LU and Boris Johnson nearly two and half years on.
"The reports of what happened on that day will still send a shiver down the spine of Tube users and no-one should underestimate the role played by a fast-acting Tube driver in saving lives as the grinder chased behind the train. Against that background the dangerous talk of driverless operation should stop right now."