Trains are being held at a platform after reports of a fire in a tunnel next to the tracks.
Services between Bexhill and Hastings were held in stations while the fire was investigated near St Leonards Warrior Square.
Passengers are being advised to allow an extra 30 to 40 minutes due to the diversion, however services are reported to be on the move.
A Southern Rail spokesman said: “We've received reports of a fire next to the track between Bexhill and Hastings.
“Trains will be held in platforms whilst the reports of a fire are investigated further.
“If you are travelling this evening, please allow at least an extra 30-40 minutes to complete your journey as this may involve you using an alternative route.”
However, Southeastern Railway, who also run trains in the area, reported that despite safety checks in the tunnel no fire was found and lines had re-opened.
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