A signalling problem at Horsham is delaying all trains through stopping there this evening (Tuesday December 4).
There are now delays of up to 45 minutes on the route between Three Bridges and Barnham via Horsham in both directions.
The 16.05 Horsham to Bognor Regis had to be cancelled due to signalling problems and the problem is likely to persist into the rush hour.
Passengers are advised to check times before they travel by using National Rail Enquiries real-time Journey Planner or calling TrainTracker on 0871 200 49 50.
Meanwhile disruption continues on the Horsham to London Victoria via Warnham line after a landslide last week. Southern is unable to operate a full timetable on this route until all remedial work has been completed.
A revised weekday train timetable is running until further notice.