British Transport Police (BTP) officers are continuing to investigate after a train guard was threatened while trying to carry out a routine ticket check.
The incident happened on board the 1.18pm Sheffield to Leeds service shortly after the train departed Sheffield station.
PC Mark Mason, of BTP Sheffield, said: â€œThe guard began walking through the carriages asking to see passengersâ€™ tickets.
â€œOne man did not have a valid ticket and was asked by the guard to leave at the next station, at which point he became abusive. When the train arrived at Meadowhall station he got off but continued to shout abuse, including threats of violence, from the platform.â€
As part of the investigation into the incident on Monday, 24 March, officers have conducted plain clothes operations on local trains and also provided advice and support to the victim, a 54-year-old man from Rotherham.
They are now asking for the publicâ€™s help in identifying a man who they believe might be able to assist their investigation.
PC Mason added: â€œI am very keen to speak to the man pictured as I think he might have important information about what happened. If you know who he is, or have any further information about the incident, please get in touch.
â€œAll rail staff have the right to come to work without the fear of abuse and BTP will always fully investigate all reports we receive.â€
Anyone with information is asked to contactÂ British Transport PoliceÂ onÂ 0800 40 50 40, orÂ text 61016, quoting reference PSUB/B6 of 12/06/2014. Information can also be passed anonymously to the independent charity Crimestoppers onÂ 0800 555 111.