A spokeswoman for British Transport Police said it was called to the station just after 7pm to reports a person had been struck by a train.
She said BTP officers were currently at the scene along with paramedics from Yorkshire Ambulance Service, who were treating a man believed to have been hit by a train.
She was not able to comment at this stage on the extent of the man's injuries.
A spokeswoman for the ambulance service said it was called at 6.58pm and a patient was being taken to Northern General Hospital.
The incident is causing major disruption to train services in and around Sheffield.
Northern Railway said all services between Sheffield and Barnsley were subject to cancellation, delay or revision, with disruption expected until 9pm.
It said rail replacement buses had been requested to cover the affected routes.
National Rail said at 8.35pm that lines had now reopened. It said services between Sheffield and Doncaster/Barnsley were expected to be disrupted throughout the night.