A woman who was killed on a train may have been leaning out of a window when she suffered a blow to the head, police have said.
The victim, who has not been identified, sustained serious head injuries on a service bound for Bristol Temple Meads station, between Bath and Keynsham, on Saturday evening.
Her death is not being treated as suspicious and the Rail Accident Investigation Branch has been informed.
A spokesman for British Transport Police said: "We were called at around 10.10pm following a report a woman had received serious head injuries while travelling on a train between Bath and Keynsham.
"Officers from British Transport Police attended along with colleagues from Avon and Somerset Police and South Western Ambulance Service, but despite their best efforts the woman died at the scene.
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"Our investigation remains at an early stage, but initial inquiries suggest the woman may have been leaning out of a window when she suffered a blow to the head.
"Officers are currently working to confirm her identity and inform her next of kin."