A young woman who died after leaning her head out the window of a train door did so despite a warning sign, an initial report has found.
Bethan Roper, 28, from Penarth, Wales, suffered a fatal blow to the head on 1 Dec 2018 after being struck by vegetation while putting her head out a window.
The Rail Accident Investigation Branch (RAIB) also found that the area around the door was a "cluttered environment", so the warning sticker may not have been easy to see.
The train was travelling at 85 mph as she opened the window of the old-style door, on which the window can be manually opened, and leaned out.
The RAIB said that a yellow "Caution" label above the door on the Great Western Railway train said, "Do not lean out of window when train is moving."
A full investigation, yet to be released, will examine what is in place to "control the risks from persons leaning out train windows, including the threat from vegetation".
The incident occurred at 22:04 near Twerton, and the charity worker was pronounced dead at Bristol Temple Meads station shortly after 22:10.
The young woman was returning to Wales with a group of friends after a day Christmas shopping in London with friends.
She was on the London Paddington to Exeter service with her female friends, who were said to have been in a "state of shock" by witnesses after the tragic accident.
Ms Roper was described by friends and family as a tireless activist who spent her life working to help others.
The young woman worked for the Welsh Refugee Council charity and was the chairwoman of Cardiff Young Socialists, and was credited with helping save a local fire station facing job cuts.
Her father, Adrian Roper, released a statement after her death saying his daughter "enjoyed life to the full whilst working tirelessly for a better world".
One of her friends, Ross Saunders, told Wales Online at the time that she was "always kind and sincere", with a "will of steel", and "utterly intolerant of injustice".
A spokesman for British Transport Police (BTP) said a day after the incident, "We were called at around 22:10 following a report a woman had received serious head injuries while travelling on a train between Bath and Keynsham.
"Officers from BTP 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.
"Our investigation remains at an early stage, but initial inquiries suggest the woman may have been leaning out a window when she suffered a blow to the head."
Helena Horton.