An 18-year-old man from East Sussex has been arrested following a "violent attack" on a train conductor after a dispute about change for a ticket.
The 36-year-old conductor was put in a head lock in the incident on a train between Pevensey and Hampden Park.
British Transport Police said several people came forward with information about the incident, on 17 March.
The man, from St Leonards, was arrested on Wednesday and bailed until 31 August pending further inquiries.
"This was a very violent attack on a man who was simply trying to do his job," said Pc Paul Gardner.
"As a result of an appeal a number of people came forward with information and I would like to thank them."
He said several people were in the carriage at the time and asked anyone else who saw the attack to contact police.