A train driver was injured at a level crossing, Network Rail said.
The incident involved a freight train and a tractor at Kisby level crossing near Ely, Cambridgeshire at 9.10am on Thursday.
The emergency services are on the scene.
A Network Rail spokesman said the train driver received minor injuries, while the tractor driver was unhurt.
Three of the train’s wagons derailed and will need to be recovered.
Passenger services between Ely and Peterborough are expected to be disrupted for the rest of the day.
Network Rail’s head of safety for Anglia, Richard Tew, said: “We are on site with the emergency services and working with all parties to fully understand the circumstances.”