Poor maintenance has been blamed for the derailment of a Norwich to Cambridge train in September 2006.
The Rail Accident Investigation Branch (RAIB) concluded road traffic dislodged an "inadequately" fixed safety panel at Croxton level crossing near Thetford.
Rail sleepers under the crossing were also incorrectly positioned, it said.
Network Rail has since inspected similar crossings to ensure such defects are corrected and maintenance crews have been given extra training.
The only injury which resulted from the inadequate maintenance work was to a car driver who suffered whiplash when crossing the line before the train arrived.
Early on the morning of 12 September 2006 a "One" train was travelling at 87mph when it hit a dislodged level crossing surface panel at Croxton and derailed, the report said.
The train ran for a further 500 yards (463m) before it stopped. There were no injuries on board.
Recommendations made
The line was closed for the day to allow repairs to the track and the fitting of a new panel to the level crossing.
The investigation found that a tanker-trailer lorry had dislodged the panel nine minutes before the train arrived.
"The panel was inadequately supported because the panels became shorter due to road traffic loading, and the sleepers under the crossing were incorrectly positioned," the report said.
"Application of the panels had not been carried out to required standards at Croxton level crossing and maintenance crews had not acted appropriately after previous reports of the panel not being secure."
RAIB made 11 recommendations relating to the installation and monitoring of panel level crossings.
'Good safety record'
Network Rail has carried out level crossing panel inspections to correct any similar defects. It has also improved staff training.
A Network Rail spokesperson said: "We are currently reviewing the recommendations made in the RAIB report.
"Following the incident itself, we immediately carried out level crossing panel inspections to correct any such deficiencies on the network and improved staff training in the maintenance, standards and risks associated with these crossings.
"Fortunately, incidents at level crossings are very rare and we have a good safety record."
One's rail services are now provided by National Express East Anglia.
^ Back to top | BBC Sport Home | BBC Homepage | Contact us | Help | ©
~RS~q~RS~~RS~z~RS~31~RS~)