A person has been hit by a train.
The incident happened when a person struck on the railway at Redhill, Surrey, and this is having knock-on impacts on Brighton mainline services.
The man was a workman for Network Rail and has now been airlifted to hospital.
A British Transport Police spokesman said: “Our officers were called to the Redhill tunnel around 10.50am to reports to a man had been hit by a northbound train.
“South East Coast Ambulance Service are attending to the man who has a suspected broken arm.”
A spokeswoman for Southern Rail said people can expect delays of up to 45 minutes and short notice alterations or cancellations to services.
Severe delays remain on Southern train services between London and Gatwick Airport and Brighton.
Gatwick Express services between London Victoria and the airport have also been suspended. London Buses, First Capital Connect and First Great Western are accepting Southern tickets.