An earlier broken down train at Ore is resulting in disruption between Hastings and Ashford International, according to Southern.
Earlier today, the 6.46am Eastbourne to Ashford International service developed a fault at Ore station, Southern said.
This service has now moved however some services became delayed in a queue behind.
In a statement, Southern said: “Between Ore and Ashford International there are several sections of single track which trains travelling in both directions share the use of. “Services have become further delayed in both directions whilst waiting for this single line to become available to use.
“Train services running through these stations are returning to normal, however some may still be cancelled or delayed by up to 10 minutes.
“As train carriages and crew are not in the correct places to start their next journeys, it has taken time for services to begin to return to normal.
“You should check prior to travelling and allow extra time to complete your journey this morning.”
Southern said disruption is expected until 10.30am.