British Transport Police (BTP) are investigating after a fight between two men on a busy train travelling between Edinburgh and Glasgow on Saturday, March 7, alarmed other passengers and rail staff.
The men, who were in a group of five, began fighting in the rear carriage of the 22.30 Edinburgh Waverley to Glasgow Queen Street service, not long after it left Edinburgh. It is believed they were both injured during the brawl.
Three of the group alighted at Linlithgow and two got off at Falkirk High station.
Constable Thomas Griffin, the officer in charge of the enquiry, appealed for anyone who was on the train or at the stations and has information regarding the incident to get in touch.
British Transport Police can be contacted on 0800 40 50 40 or by texting 61016.
Information can be given anonymously to Crimestoppers on 0800 555 111.