A train was engulfed in flames on Friday morning causing disruption to the rail network and thick black smoke to fill the air.
Six fire engines were called to Dunton Green train station to battle the blaze.
Nearby residents had been advised to close their windows and doors to avoid inhaling the smoke and told to stay away from the area.
The fire was extinguished around 7.45am, the BBC reported.
Network Rail tweeted that both lines between Sevenoaks and Orpington have been blocked, and warned that it “could take most of the morning to clear.”
They added: “Once we’ve moved the damaged tamper, a machine which restores the level of the track, we’ll need to check for damage to the track & what repairs might be needed.
“We don’t know yet what caused the fire but are working with Kent Fire and Rescue who are investigating.
“We have lots of people on site right now working to get passengers moving again and that’s our priority.”
Southeastern Railway is running a bus replacement service and diverting some trains via other stations.
There are no reports of any injuries and the cause of the fire has not been established.