A train guard was assaulted by passengers on an Edinburgh to Dundee service.
A group threw a container of alcohol at him at Inverkeithing.
The incident happened around 7.20pm on March 2.
The aggressive group also threw a glass bottle which smashed off the train doors.
Anyone with details can contact British Transport Police by sending a text to 61016 or by calling 0800 40 50 40 quoting reference 602 of 02/03/2019.
Alternatively, you can call Crimestoppers anonymously on 0800 555 111.