A woman who died from serious head injuries while on a train was a charity worker returning from a Christmas shopping trip with friends.
Bethan Roper, 28, from Penarth was on the Bristol Temple Meads-bound service on December 1.
Police believe her injuries were caused when she leaned out of a train window.
The charity worker and chair of a young socialist group was returning home after spending the day at Bath's Christmas Market with friends when she suffered the fatal blow to her head.
British Transport Police said, a day after the incident, its initial inquiries suggested Miss Roper may have been leaning out of a carriage window at the time.
The spokesman said the incident was reported to the Rail Accident Investigation Branch, and that the death was not being treated as suspicious.
Miss Roper was working for the Welsh Refugee Council at the time of her death, having graduated from Cardiff Metropolitan University in 2013.
She was also a campaigner and chairman of Young Socialists Cardiff.
Her father, Adrian Roper, 63, released a statement describing his daughter as being "beautiful in every way".
Mr Roper said: "Bethan had a big close network of friends with whom she loved to go to music festivals and clubs or just spend time with, talking and laughing.
"She also travelled the world for six months with her soul-mate, Lizzy, making more friends from around the world. They also went cage-diving with sharks in South Africa several times together.
"She was an avid reader, podcast listener and film watcher, with a deep insight into the world around her.
"She enjoyed life to the full whilst working tirelessly for a better world. She was also a much loved sister, daughter, grand-daughter and niece.
"All of us who knew Bethan have been very privileged. She was beautiful in every way. Our pain couldn't be sharper or more justified, but I know that her goodness and fullness of spirit will live on in our hearts and actions."
An inquest into her death is expected to open next week.