Network Rail has issued an update on its work to restore services after a major landslip between Godstone and Edenbridge in Kent closed the railway on 22 December 2019. The line is now expected to reopen sometime in March 2020.
The slip is one of the largest the railway of the South East has faced in many years. It was discovered when a train driver noticed the track starting to dip on a 12-metre-high embankment that carries the railway over the Eden Valley.
The landslip followed a month of rain in one week, on already saturated ground. This winter has seen a total of six months rain in the space of three months.
The Redhill-Tonbridge line was commissioned in 1836, when the science of earthworks was less well understood than it is today. The railway crosses the Eden Valley on an embankment built of Wealden Clay, dumped on alluvial soil (gravelly soil laid down by the River Eden). After extreme rain, the River Eden burst its banks and soaked the already saturated ground around the railway. The clay embankment – built with a very steep-sided bank – then slipped towards the river in what is called a “deep rotational failure”.
Network Rail route director for Kent, Fiona Taylor, said: “This landslip is a serious challenge for us, not just because of the scale of the slide but also the remoteness of the location. To give you some idea of the size of the slip, we are having to bring 40,000 tonnes of stone in from as far away as Carlisle to build the bank back up again and we’ve had to cut through the remaining part of the railway just to gain access to it.
“Our passengers have been very patient with us and we are doing everything we can to speed this project along and working 24/7 to get the railway open. Once we have an exact date, we will let everyone know and if we can achieve that earlier than the end of March then we will.”
To get access to the slip, engineers from Network Rail and contractor BAM Nuttall have built a road across a field and cut a section of the embankment out, while building a temporary bridge to carry vital cables over the gap. Around 40 trains are being planned to bring 40,000 tonnes of recycled railway ballast to site as the local roads are too narrow to allow lorries access. This crushed and washed old ballast will be built up into a shallower slope that will be stronger than the one that failed.
While that work is going on, Network Rail is working on plans to reinforce the longer, 400 metre section of railway that crosses the Eden Valley at this location, to stop any future slips. This work will continue without affecting trains.
Network Rail chief executive Andrew Haines visited the site, as this video records: