The driver of a car that was struck by a train in Cambridgeshire did not have permission to be on the level crossing where it was hit, Network Rail has confirmed.
A man in his 40s was taken to Addenbrooke's Hospital with serious head injuries following the crash yesterday afternoon.
A Land Rover Discovery was hit by a train between Cambridge and Ely on a level crossing where drivers must call ahead to a signaller before going over the track.
But a spokesman for Network Rail has confirmed no call was made.
Mr Johns said checks had also been made to confirm there were signposts up explaining the procedure to motorists approaching the crossing.
He said the official investigation was now a police matter but said Network Rail would continue to look at whether there was anything it could do to improve safety at the site.
The organisation, which is in charge of the rail infrastructure across the country, has been attempting to close level crossings wherever possible.
But Mr Johns said the crossing involved in yesterday's crash was not thought to be one of those due to be closed.