Brighton Main Line Improvement Project

Since September 2018 we have been carrying out a major project to improve reliability and performance for passengers on the Brighton Main Line.

The work is almost complete. We have made great progress so far, there are just a few more line closures between Three  Bridges and Brighton & Three Bridges and Lewes.

The improvement works on the Brighton Main Line are a key part of a £300 million government-funded programme to tackle delay hotspots and boost the reliability of the railway in the south east, including the expanded Thameslink network.

The Brighton Main Line is a key rail route, connecting Gatwick Airport and the south coast with London, and is used by 300,000 people each day.

The performance on this part of the network needs to be improved and we are working to deliver that. The sections of railway where engineers are working is responsible for more delays to Southern, Gatwick Express and Thameslink passengers than any other. Without this programme of work, reliability on the Brighton Main Line will deteriorate in the months and years ahead, leading to more delays for passengers.

Key Weekend Dates

March - May 2019

  • March - Saturday 2 and Sunday 3, Saturday 23 and Sunday 24, Saturday 30 and Sunday 31
  • April - Saturday 6 and Sunday 7
  • May - Sunday 5 (01:30 - 09:30 only)

This will mean changes to train services across the Southern, Gatwick Express and Thameslink networks and longer journey times for some passengers.

  • No trains will run between Three Bridges and Brighton or between Three Bridges and Lewes on these dates.
  • Brighton and stations to the west will have trains to and from London, but these will be diverted via Littlehampton and Horsham.
  • No direct trains to London from Lewes or Eastbourne.

Passengers wishing to travel on these dates will need to allow considerably more time for their journeys and should expect to use either diverted trains via longer routes or a replacement bus or coach to connect with rail services.

What are we doing?

The improvement project is focusing on the southern end of the Brighton Main Line between Three Bridges and Brighton. Major engineering work is planned for the Victorian-era tunnels at Balcombe, Clayton, Haywards Heath and Patcham and the railway which runs through them.

We are stemming leaks into the tunnels and improving drainage, while the third rail power supply and signalling are also being replaced or upgraded.

Elsewhere on the closed section, we are replacing the track and sets of points, which enable trains to switch between tracks.


Progress so far

Find out more about the engineering work completed during the 9-day closure period.

The time-lapse below shows work at Balcombe Tunnel Junction which was renewed and upgraded as part of the 9-day closure, replacing 600 metres of track, improving the layout of the junction and replacing switches and crossings.

Visit the Brighton Main Line website to see the works completed so far.

Contact us

For more information and travel advice email: or visit