British Transport Police officers are appealing for information after a train guard was threatened while carrying out a routine ticket check.
The incident happened on board the 1.18pm Sheffield to Leeds service shortly after the train left Sheffield station.
The guard, a 54-year-old man from Rotherham, was walking through the carriages asking to see passengers’ tickets.
PC Mark Mason, of BTP Sheffield, said: “One 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.”
As part of the investigation into the incident on Monday, March 24, officers have conducted operations on local trains.
They are now asking for help in identifying a man who they believe might be able to assist their investigation.
PC Mason added: “I 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.
“All rail staff have the right to come to work without the fear of abuse and BTP will always fully investigate all reports we receive.”
Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference PSUB/B6 of 12/06/2014. Information can also be passed anonymously through Crimestoppers on 0800 555 111.