The Tunbridge Wells to Hastings rail line will close for seven days next month as action is taken to mitigate against landslips.
The closure will be timed to coincide with the October school half-term to minimise disruption.
Bus replacement services will be provided but passengers should check their times on Southeastern or National Rail inquiry websites before they travel
Engineers are preparing to strengthen the resilience of a section of track between Tunbridge Wells and Hastings known for frequent landslips.
No trains will run in either direction between Saturday, October 23, and Friday, October 29.
The work will centre on the Victorian-built Wadhurst Tunnel, which has seen its steep-sided entrances increasingly affected by heavy rainfall and subsidence in recent years.
A similar project has recently been completed at Bearsted near Maidstone. Both schemes involve soil nails driven into the cutting face at both ends of the tunnel, to hold them fast.
It is hoped that doing the work over a concentrated period of seven consecutive days would significantly reduce the overall disruption to passengers.
Network Rail infrastructure director Bob Coulson said: "The steep cutting at Wadhurst was dug more than 170 years ago and has suffered from a number of landslips in recent years, causing significant disruption to passengers on this key route between the coast and central London.
"These stabilisation works are vital for us and Southeastern to provide more reliable train services and by doing this work in one block, we will avoid having to close the line for countless weekends in future.
"We’re rebuilding our railway for the future and it’s clear that closing the railway on weekends – when it’s now at its busiest – is not the right way forward.
"We will also be tackling other vulnerable sites on the line over the seven days the route is closed, to make the best use we can of the opportunity.”
They include Strawberry Hill, Church Settle, the Telham Road cutting and the Nevill Golf Club embankment.
Network Rail will also be carrying out other maintenance work at stations when they are closed during the blockade.