New information has revealed "at least 20" hunting dogs could have died on a level crossing near Diss.
According to a source at Greater Anglia the train driver reported "100 dogs being on the track" at the Great Moulton level crossing during the incident at 8.45am yesterday.
Those numbers have been disputed by the British Hound Sports Association (BHSA) which says six dogs strayed from their pack while being exercised by the Dunston Harriers and that the number of hounds in the group "would not have been 100".
The number of dogs who died in the incident has not yet been released, however it is thought their carcases were recovered by rail workers.
The new information, seen by this newspaper, also says the driver applied the brakes upon seeing the dogs but was unable to stop the train in time.
After an inspection, the train carried on to Diss where the service terminated.
The crash was also reported to British Transport Police (BTP).
A spokesman for the force said: "BTP received a report of dogs on the tracks near Great Moulton at 9.07am.
"Trains passed through the location on caution for a short time.
"There were no further sightings of dogs on the railway."
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