We’re busy strengthening the near the railway around Britain, including in Cumbria, where a £3.5m investment will lead to more reliable journeys for passengers.
What causes landslips? How do we try to prevent them? And how do we respond when they happen?
Landslips happen on the railway when soil, rocks and earth fall on to and cover the track. This is often after long periods of heavy rain, when the ground becomes saturated with water.
Landslips can cause a lot of disruption and delays on the railway by obscuring the track. A train can’t swerve to avoid debris on the line, so we will often need to re-route services.
Our specialist geotechnical engineers work across Britain to stabilise and repair weakened assets, enabling a network more resilient to future risk events, such as extreme weather.
We’re working hard on different projects to prevent landslips
In Cumbria, engineers are upgrading the embankments along the railway to improve journeys on the West Coast Main Line between Oxenholme and Carlisle.
We’re making the earth embankments less steep and the ground more secure at two stretches of railway: one north of Oxenholme and the other just south of Carlisle.
The embankments are made from a mix of ash and local material excavated nearby.
The area has suffered from significant damage in the past; Storm Desmond hit the site north of Oxenholme in December 2015.
Richard Hockney, a project manager at Network Rail, said: “This essential work as park of the Great North Rail Project will make this busy passenger and freight route more reliable in the future.
“Our teams have worked hard to secure a total of 1.5km of embankment over the last few months, working around challenges brought on by covid-19.”
In Anglia, we protected the tracks on the Sudbury branch line after our engineers discovered heavy rain had caused the embankment to slip between Wakes Colne and Bures at the start of the year.
Engineers worked for more than 11 weeks to remove spoil, support the embankment and build a wall, using nearly 200 tonnes of materials.
We also cleared the drainage system and fitted new parts to improve drainage.
This will all prevent the embankment from slipping further onto the tracks, which would have caused damage and led to disruption for passengers.
The area is also home to many badgers and the work was designed in a way to prevent disturbing the setts.
South of England
Our engineers have completed major repairs and upgrades to the railway around Templecombe, Gillingham and Sherborne to stabilise the ground.
We had to impose a speed restriction in the Templecombe area of Somerset after a landslip late last year. We’ll be able to remove this speed restriction and allow trains to travel faster through the area soon thanks to the works.
The project included:
- Inserting four-metre steel nails into the slope at Templecombe to stabilise the cutting to prevent further landslips
- Building a 40-metre gabion wall – wire baskets filled with stone – at the bottom of the cutting for extra protection
- Installing 400 metres of new track in the Gillingham area for more reliable journeys.
Engineers are also strengthening a railway slope close to St Catherine’s tunnel in Guildford after a landslip in December, with work expected to last until November.
Analysis by a team of geotechnical experts at the time of the slip found heavy rain had damaged the area.
Our engineers have been working at the site since December to protect the railway where it is cut deep into the hillside. The team are securing the slope by inserting steel nails, reinforced by cement.
We have also covered the cutting face with a protective netting to prevent more sand falling onto the track. The area will also be reseeded and we are working with experts to promote future regrowth of vegetation.
We’re working on the embankment and drainage at Slochd between Perth and Inverness on the Highland Mainline.
The project, which will last until November, will help protect against landslips and rockfall and address a known flooding risk. This has caused delays and cancellation to passenger journeys twice in the past year.
The £4.8m investment will involve the installation of a new piped drainage system and earth-bunds, which helps drainage. We will also install concrete-lined ditches to manage the flow of water away from the railway to culverts and natural water courses.
How else are we’re reducing delays caused by landslips?
- It’s important we identify the sites prone to landslips to ensure we keep passengers and our engineers safe. We use helicopters equipped with laser imaging, detection and ranging to do this.
- Where we know sites are at risk of landslip, we use motion sensors and CCTV to detect soil and rock movement. These sensors send an alarm to the signaller, who will stop the train if alerted and wait until the area has been inspected by engineers.
- We can also stabilise the slope by putting in drainage or using steel rods or soil nails.
- If these options are insufficient, we will re-profile the slope to reduce its angle, making it less prone to a landslip.
- When we get flood warnings from the Environment Agency and Flood Forecasting Centre, we send people and equipment to the at-risk areas so we’re in a position to act quickly.