Transport police are searching for a man who threatened two members of rail staff at Meadowhall Interchange.
A man is alleged to have made threats to punch the two workers as they attempted to check his rail ticket.
The incident happened in Wednesday, November 16, at around 1.20pm.
Investigating officer PC Stephen Slocombe said: “Two members of rail staff were checking tickets at the top of the stairs near to platform three. A man was asked to show his ticket but he declined.
“When asked again, he swore at staff, became abusive and made threats to punch them.”
PC Slocombe added: “These staff members were just doing their job. Abuse or threats to rail staff will not be tolerated.”
The man is described as white, unshaven, around 5ft 2ins tall, of medium build, with short blonde hair, and was wearing a green jacket and blue trousers.
Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference PSUB/B10 of 016/01/15.
Information can also be passed anonymously to independent charity Crimestoppers on 0800 555 111.