Network Rail engineers are preparing to tackle a 40 metre-long landslip that blocked the line at Newington, near Sittingbourne, earlier this week, with work set to begin tomorrow.
The slip closed the railway on Wednesday and Thursday, while a temporary fix was put in place to allow the line to open for two days.
However, the scale of the problem meant a permanent solution had to be put in place as soon as possible.
The line will close from the last train on Saturday night (23 January) until the first train on Monday, 8 February.
This will mean no Southeastern trains will be able to run between Gillingham and Sittingbourne and Thameslink trains from London to Rainham will terminate one station early, at Gillingham. A bus replacement service will run instead.
Network Rail’s route director for Kent, Fiona Taylor, said: “This has been a difficult week for passengers on the railway through Newington and I’m really sorry we’ve had to take this drastic action so soon after reopening it. We’ve kept trains safe throughout the week but we don’t want to cause any more disruption and the best way to achieve that is to close the railway and rebuild it.
“It’s not an easy decision but the scale of this problem means there’s no way of fixing it without stopping trains and the sooner we do that, the sooner this line can open safely again. I'd really like to thank our passengers for their patience in these difficult times.”
The slip occurred on a section of railway built in 1858, where the line is cut 13m deep into the surrounding hill. After days of heavy rain, the top section of the cutting side gave way and slowly slipped downhill towards the track.
Over 300 tons of spoil was removed before the line could be reopened and there’s still more to go.
Jenny Saunders, Customer Services Director for Thameslink, added: “Due to Government restrictions, you should only be travelling if your journey is absolutely essential. I'm sorry to our Thameslink passengers affected by this work - please make sure you check the latest travel advice before setting out.”