British Transport Police have released CCTV images after members of rail staff were attacked at Bournville Railway Station.
The incident happened at 9.45pm on Friday 15 November last year.
Six men are reported to have been on a train arriving at Bournville station. As the train pulled into the station they pulled its emergency stop levers.
They then stood on the platform and spray painted the side of the train.
During the incident members of rail staff were assaulted after challenging the group.
One of the victims was sprayed in the eyes with the spray paint and needed to be taken to hospital for treatment. He was released the following day.
Officers would like to speak to the men in the images who may have information that can help their investigation.
Anyone who knows them can contact British Transport Police by texting 61016 or by calling 0800 40 50 40 and quoting reference number 1900098847. Alternatively, people can call Crimestoppers anonymously on 0800 555 111.