Questions will be asked whether or not a tractor driver asked permission to cross a railway line before his vehicle collided with a train, causing major disruption and injuries to passengers.
Rail investigators are still looking into the events that led to the collision on Sunday, which saw a tractor collide with a passenger train at around 12.30pm at Roudham.
Seven passengers were treated at the scene and the drivers of both the train and the tractor were taken to hospital.
Vehicle drivers crossing the track are required to phone through for permission from a signaller before lifting the barriers at the unmanned level crossing and continuing.
The case is now in the hands of the British Transport Police (BTP) and Rail Investigation Branch.
A spokesman for the BTP said it would be releasing an update on the investigation in the coming days, but a spokesman for Network Rail confirmed that questions about the tractor driver's conduct would be asked as part of it.
The spokesman also said the incident had caused damage to the tracks at Roudham, which was repaired that night by engineers.
Some staff remained on site yesterday as they dealt with repairs to the adjacent pedestrian footpath.
The spokesman said the level crossing was a private crossing for farm workers.
This newspaper understands that the crossing is most regularly used by workers at Roudham Farm, with the railway line splitting its land just south of the A11.
The farm is owned by Tim and Ellen Jolly. Mrs Jolly is a Conservative Breckland councillor for Harling and Heathlands, which covers Roudham.
When contacted, Mrs Jolly said she was unwilling to comment on the investigation, but said her sympathies were with the injured drivers and passengers.
Further eyewitness accounts have also begun to emerge.
Sarah Drake, 29, from London, said she was travelling with two friends and her girlfriend when the incident took place.
'We heard this loud noise and then the train just started to judder, almost like it was going from side to side.
'It was like the train was out of control and we knew we'd hit something.
'There was a feeling like we were going to come off the tracks and it's a miracle we didn't,' she said.
Miss Drake, who was travelling with her shoulder in a sling having broken it in a climbing accident two weeks previously, added that emergency services had been 'excellent'.
Chloe Smith, MP for Norwich North and co-chairman of the Great Eastern Mainline Rail Taskforce, also commented on the incident yesterday, and another in which a person was killed at a level crossing in Cringleford.
She said: 'It is very concerning to have two accidents in two days, one of them fatal today near Norwich.
'My thoughts and sympathies go out to all who have been tragically involved, including the staff and emergency services.
'I will be speaking urgently to Greater Anglia and Network Rail to see what lessons can be drawn immediately and in the long term for better safety on our railway in Norfolk, while we go about securing the improvements to service that we've been campaigning for over many years.'
We have been asked to clarify that, at unmanned rail crossings, it is the responsibility of the road user to contact the signaller to request permission before crossing the railway line and not as reported in yesterday's EDP.
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