Passengers are being warned of disruption to their journeys this weekend, as Network Rail will be replacing two damaged rails on the Brighton Main Line.
The work is due to start on Saturday night and will not be finished until 2pm on Sunday.
Due to the position of the problem it means train services will be extremely limited across the majority of the route.
There will only be one train every 90 minutes between Brighton and London, via Gatwick Airport.
Due to other major engineering work on other routes there will be an extremely limited replacement bus service.
Network Rail and Govia Thameslink Railway’s joint network operations director, Mike Paterson, said:
“We’re really sorry to be causing such disruption this Sunday, especially with engineering work elsewhere on our railway at Horsham.
“Our advice is to travel only if you absolutely have to while the work is taking place on Sunday morning, as we simply do not have the resources to run enough buses to carry everyone safely.
“We’ve got one line open, which will allow a very limited train service to run, but nowhere near what we would need to carry the normal number of passengers to the beach on a Sunday morning. Our team has tried to find different ways of getting this job done but we can’t put it off any longer and have to take this action now."
Journey planners will be updated tomorrow (14th of August).