British Transport Police officers are currently at the scene of the incident in Kirton Lane, Thorne.
It is understood that a bus has struck a level crossing barrier causing damage to both the vehicle and barrier.
It is not clear if the barriers were down or raised at the time. It is not thought anyone has been injured in the incident.
A spokesman said: "Officers are at the level crossing in Doncaster after reports that a bus struck a level crossing barrier causing damage.
"An investigation is underway to establish how the bus came to strike the barriers.
"Engineers from Network Rail are also on scene making repairs to the barrier."