Police are trying to trace three youths who racially abused and assaulted a train guard at Meadowhall station.
They struck at around 9.45pm on Wednesday, March 9 after being challenged about boarding a train from Chapeltown to Meadowhall without tickets.
Investigating officer PC Mark Mason said: “The three youths boarded a train at Chapeltown to Meadowhall without tickets.
“When challenged by the train guard during a routine ticket check they subjected him to racist abuse.
“When the train arrived into Meadowhall the three teenagers then attacked the guard, throwing punches and hitting him on the neck.”
One youth was around 15 years old, short, of a medium build with brown hair.
He was wearing a brown jacket, a woolly hat and a brown cross body bag.
The second was around 16, chubby and had curly, brown hair.
He was around 6ft tall and was wearing a black or dark blue hoody, blue jeans and white trainers.
The third youth was around 16 years old, around 6ft 1ins tall, skinny and had brown hair.
He was wearing a hooded top with a black jacket over the top, black rimmed glasses and blue jeans.
PC Mason added: “This was a frightening experience for the train guard who was left shaken by the actions of this group.
“The victim was simply doing his job and to be subjected to this kind of behaviour is completely unacceptable.
“No one should be made to feel fearful for their safety on the rail network. Please help us identify these young men.”
Anyone with information should call British Transport Police on 0800 40 50 40.