Following a fault with the signalling system earlier today (Friday April 28) between Horsham and Barnham all lines are now open.
Southern say that train services running through these stations are returning to normal but some may still be cancelled, delayed or revised.
Disruption is expected until 4pm today.
The earlier fault with signalling equipment in the Horsham area required emergency safety repair work which has been carried out.
Southern are working to get displaced stock and crew to their current locations in time for the evening peak.
Southern ask passengers to check before you travel and allow extra time for your journey.