No trains will run between the stations today (Saturday, January 15) and tomorrow (Sunday).
Trains between London Victoria and Brighton will run to a revised timetable and be diverted via Littlehampton.
On Saturday, only trains between London Victoria and Portsmouth / Southampton will stop at additional stations between Horsham and Barnham. There will also be a reduced service between Brighton and Lewes.
Buses will be replacing Thameslink trains between Three Bridges and Brighton.
A slightly reduced service will run between London Blackfriars and Three Bridges.
Thameslink services to / from Horsham will call additionally at Purley, Earlswood and Salfords.