CCTV pictures have been released of a group of men who attacked rail staff at Bournville Station, spraying one of them in the face.
The attack happened at 9.45pm on November 15.
The six are believed to have been on a train and pulled the emergency stop levers as it arrived the station.
They got off and spray-painted the side of a train at which point they were challenged by rail staff.
The group then assaulted the employees and one of the victims was sprayed in the face and needed hospital treatment.
He was released the following day.
Officers from British Transport Police have appealed for anyone who witnessed the vandalism or attack or anyone who recognises the perpetrators to call them by texting to 61016 or by calling 0800 40 50 40.
Information can also be given via Crimestoppers on 0800 555 111.
Bournville Station is on the busy Cross City Line which serves Bromsgrove and Redditch, along with Northfield, Longbridge, Barnt Green, Alvechurch and Kings Norton.
