Rail investigators received reports of 'rough riding' at 'irregularity' spotpublished at 13:08 BST
We can now bring you more on the "irregularity" the report has identified on the train track where the derailment occurred.
It says that a "track geometry irregularity" existed on the approach to the site where the train derailed "prior to the accident occurring".
As well as this, there was "evidence of previous track maintenance activity" in the area.
And since the incident, the Rail Accident Investigation Branch says it has received "several reports of rough riding" at the same location, from passengers on other trains.
It also marks on the rails are "consistent with the wheels of the derailed rear vehicles having climbed over the rails".

An aerial shot of the train of which three carriages fell off the tracks in Lewes, East Sussex






