Our thoughts are with the parents of Emma Lifsey and their loved ones at this very difficult time.
We will be doing everything possible in the days ahead to assist the investigation into identifying the cause of this tragic incident.
Work is continuing this morning to move the train from the incident site to allow normal services to start running again.
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Some children, particularly those who have been more directly affected, may show symptoms of stress and trauma.
A warmer day tomorrow
The threat level has been raised to critical by MI5's Counter-Terrorism Analysis Centre.