Report by ITV News Meridian's Andy Dickenson
Rail passengers in Sussex are being warned of disruption to journeys this week due to improvement works.
Sections of the track between Arundel and Three Bridges and Horsham and Dorking are being replaced as part of a £22 million project.
The track from the 1980s will be swapped for a new one, as well as deep cleaning, refurbishing, decorating and essential maintenance of stations along the Arun Valley line.
Network Rail says the improvement works will reduce the risk of flooding on the line.
James Pearce from Network Rail said: "This area is bad for drainage so we've replaced the drainage system in the areas, as well as replacing the track, sleepers, the stone, and ballast.
"So all of that gets replaced to improve functionality and reliability in the area."
While work is being carried out, buses will replace trains along much of the Arun Valley line, from Arundel (inclusive) to Three Bridges including Horsham and Crawley, and the Mole Valley line between Horsham and Dorking.
Rail bosses are also taking the chance to give 13 different stations a facelift.
Commuters are hoping to return to a shinier, smoother running line from Monday 23 August.