Initial inquiries into the cause of an underground commuter train derailment in Liverpool suggest a track fault.
The accident happened close to Liverpool central station
Investigators have ruled out driver, train or signalling error for the cause of the accident on 26 October 2005, according to interim findings.
The Wirral line Merseyrail train derailed in Liverpool city centre, trapping 119 passengers underground.
Union officials said the public should have been informed immediately when it emerged the driver was not to blame.
The accident happened in the one-way "loop" part of the network, about 200m from Liverpool Central station.
All passengers were led to safety within two hours and there were no major injuries after the train jumped the tracks.
An interim report on the Rail Accident Investigation Branch website said: "Initial investigations indicate that the driving and condition of the train, and the signalling mechanisms, did not contribute to the derailment."
A full report with recommendations on how to avoid a similar accident in the future will be published at a later date.
A spokesman for Network Rail, which is responsible for maintenance of the track, said the company could not comment fully until the investigation was concluded.
But he admitted: "If investigators have ruled out the driver, the train and signalling system the indicators are it really only leaves the track."
Colin Smith, of the train drivers' union, ASLEF, said he was pleased it appeared one of his members had been cleared of blame.
"An interim report should have been given straight away to give the public confidence that it wasn't driver error."
"This one, I am assuming, is down to maintenance."