The Brighton Main Line between Three Bridges, Brighton and Lewes will be closed for nine days from Saturday, 19 to Sunday, 27 February whilst essential work is carried out to tackle delays for Southern and Thameslink passengers.

In a major £15 million upgrade, engineers will work round the clock to rebuild a crucial junction, lay new track, and shore up embankments to reduce the risk of landslips. The upgrade also means the lines between Three Bridges and Brighton/Lewes will be closed on the weekends of 12/13 February, 5/6 March and 3 April for preparation and follow up works.

Southern and Thameslink will operate alternative train and bus services, but many journeys will take considerably longer than normal. No trains will run between Three Bridges and Brighton or Lewes.

Main line services will start and terminate at Three Bridges where a temporary bus hub with toilets and a refreshment stand will be provided. Replacement buses will run from the hub on routes across the closed sections of line. 100 additional customer service staff will be on hand to provide assistance.

Between London Victoria and Brighton via Gatwick Airport, Horsham and Littlehampton, there will be two buses per hour which will provide an easier and more comfortable journey than using a replacement bus but the journeys will take significantly longer.

During the closure, engineers will replace over 1,500 metres of track at Copyhold Junction, Burgess Hill, Preston Park and in Clayton Tunnel. They will also renew eight sets of points and build a new underpass at Hassocks to replace Woodside level crossing.

The work is all part of the wider Sussex Upgrade programme, which is investing more than £750 million from 2019 to 2024 to improve the railway for passengers.

Katie Frost, Network Rail’s Sussex route director, said: “The Brighton Main Line is one of the UK’s busiest routes and the rail infrastructure is among the oldest and most intensively used. These works are absolutely vital to improving performance so we can give passengers a more reliable train service.

“Doing the work in a longer 9-day closure means we can get more work done, more quickly, avoiding 20 separate weekend, evening and bank holiday closures which would be even more disruptive to passengers, the people who live by the railway and the wider economy.

“We are working hand-in-hand with our colleagues at Govia Thameslink Railway to make sure people who do need to travel when the line is closed can still go where they need to.”

Chris Fowler, Southern’s Customer Services Director, said: “We’ve been working closely with Network Rail to make sure our customers can get where they need to be while these vital infrastructure improvements are carried out. The train and bus services we’ll be running are now in the online National Rail Enquiries journey planner so please plan your journey now, and re-check closer to the time, as we might need to make further changes because of Covid.

“People can take a train confidently, knowing that Southern and Thameslink trains and stations are treated every day with a viricide that kills coronavirus for weeks at a time.”

Extra work being carried out during the closure includes:

• Rebuilding a collapsed culvert in Balcombe tunnel;
• Installing fibre optic cable between Three Bridges and Brighton to enable 5G connectivity along the route;
• Embankment and cutting stabilisation at Balcombe, Lewes, Haywards Heath and Hassocks to reduce the risk of landslips;
• Maintenance in Clayton tunnel including brickwork repairs;
• Tree planting and biodiversity improvements at Haywards Heath, Wivelsfield, Burgess Hill, Hassocks, including a dormice bridge at Balcombe;
• Refurbishing Spatham Lane level crossing near Cooksbridge.

Owing to the ongoing impact of Covid on timetables, should plan ahead and re-check closer to the time of travel at nationalrail.co.uk