We will be improving reliability and performance for passengers on the Brighton Mainline.
The work is part of a programme to tackle delay hotspots and boost reliability of the railway in the South East.
Used by 300,000 people each day, the Brighton Mainline connects Gatwick airport and the south coast with London.
The improvement project will focus on the southern end of the Brighton Mainline between Three Bridges and Brighton. Major engineering work is planned for the Victorian-era tunnels at Balcombe, Clayton, Patcham and the railway running through them.
Upgrade work and line closures
Most of the work has been planned to take place during school half-terms, when passenger numbers are lower, in October 2018 and February 2019.
This means there will be no trains between Three Bridges and Brighton or Three Bridges and Lewes from Saturday 20 to Sunday 28 October 2018, and from Saturday 16 to Sunday 24 February 2019. The line closures will allow upgrades to a section of railway that’s responsible for more delays for Southern and Thameslink passengers than any other.