An engineering train caught fire near a railway station, blocking the line and disrupting travel.
At its height six fire engines were on the scene, close to Dunton Green station in the Sevenoaks area, a Kent Fire and Rescue Service spokesman said.
The train is being towed away from the scene and trains are now running through Dunton Green again.
There were no reported injuries and the cause is being investigated.
Two crew members were on board the train, which had been carrying out maintenance work, they were alerted to the fire by an alarm.
Looks like the crew are all out. This is a drivers worse nightmare. There going to hours of delays through #DuntonGreen while @kentfirerescue help @NetworkRailSE get the railway back up and running for @Se_Railway pic.twitter.com/bQXe0qpR1s— PatrickF1 (@HammertimeLH44) April 23, 2021
People in the area have been told they can now open windows and doors, after being advised earlier to keep them closed due to a smoke plume.
The fire was reported at about 05:15 BST and was brought under control at about 07:45, the fire service said.
Network Rail said its engineers were working to restore the level of the track before any damage could be assessed.
The train was being towed down the line to Tonbridge, the BBC's Simon Jones tweeted.
Train that caught fire at Dunton Green now being moved to Tonbridge. pic.twitter.com/ZAgtTvokA7— Simon Jones (@SimonJonesNews) April 23, 2021