The incident happened on a train travelling from Balloch, West Dunbartonshire, to Anniesland in Glasgow’s west end on Thursday.
British Transport Police (BTP) were called to Anniesland station just after 6.20pm.
The force said one person was arrested but has since been released while inquiries into the incident continue.
Three people received treatment for superficial injuries.
Anyone with information can contact BTP by texting 61016 or calling 0800 40 50 40.