More on KentOnline
Train services are unable to run between Maidstone East and London Victoria.
Southeastern has arranged a replacement bus to run between the County Town station and Swanley.
Urgent repairs are being made to the line between Maidstone East and Otford after a signalling problem in West Malling this morning.
Staff from Network Rail attended and found damage to the rail which needs repairs.
The team plan to make the track safe for trains to pass over slowly and will return later to fix it completely.
Routes are also being diverted between Ashford and Otford via Tonbridge.
Southeastern is arranging a shuttle train between Maidstone East and Ashford.
A spokesman for Network Rail said it hopes to have the line open again by 2pm and was unable to confirm the cause of the damage.