Trains between Hastings and Ashford International are currently facing disruption this afternoon (Friday, September 20).
Southern said a broken down train near Rye is causing delays to trains between both stations.
It added that services may be delayed or cancelled until approximately 3pm.
Three Oaks, Winchelsea, Rye, Appledore and Ham Street stations are not being served in either direction, Southern said.
Rail replacement buses have been requested to Ashford International and Hastings, it added.