British Transport Police officers are appealing for help to trace three people after two teenagers were attacked on a train to Colchester.
The incident occurred on Saturday, September 6, on board a Wivenhoe to Colchester train, while it was at Hythe station.
Detective Constable Alan Reed said: "The two victims boarded the train at Wivenhoe.
"After a short time they were approached by a large group who engaged them in conversation.
"As the train approached Hythe, a physical altercation occurred."
The victims – both aged 17 – suffered minor injuries.
Officers believe the three youths pictured will be able to assist them with their enquiries.
DC Reed added: "Who are the faces in the CCTV images? If you recognise any of them, or have any further information, please get in touch.
"We take all reports of violence on the rail network very seriously and are working hard to find those responsible."
Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference E-SUB/B11 of 02/11/14.
Information can also be passed anonymously to independent charity Crimestoppers on 0800 555 111.
