Students said they were forced to get off the train because it was so overcrowded
A group of festival-goers "trapped" on board an overcrowded train had no option but to pull an emergency cord and exit on to the tracks, it has been claimed.
Up to 200 passengers jumped from the train to get back to the platform at Clifton Down station, Bristol.
University newspaper Epigram reported, external students were travelling to a music festival at the time.
British Transport Police said they were treating the incident as trespass.
Sorcha Bradley, who was on board, said people got off because they felt it was "the only option".
"I felt really claustrophobic, I was very scared, I was on the verge of tears," she said.
"You expect to get on the train and travel to your destination with no problem.
"We weren't sure if the track was electrified or not so everyone was quite worried, and we were all concerned about another train coming."
The emergency stop alarm was pulled to stop the train at the weekend
Passengers claimed the train was overcrowded
A spokeswoman for British Transport Police (BTP) said officers were called to the track at about 15:30 BST following a report of people walking on the line.
Its officers helped the group "off the line and to a place of safety," it said.
"We are treating this as a trespass incident - one which caused numerous delays to services in the area and could have put lives in danger - and inquiries are currently under way to identify those involved."
Trains were cancelled between Severn Beach and Bristol for several hours due to the incident.
Julian Burnell, of Network Rail, said railway lines were "inherently dangerous places", while a Great Western Railway spokesman said railway trespass was a criminal offence carrying a maximum fine of £1,000.
