What we’re doing to help prevent landslips and the delays they cause
A landslip on the railway is generally defined as when soil, rocks and earth fall onto and either wholly or partially obscure the track.
Also known as landslides, they can occur anywhere, moving either slowly or quickly. When they impact on railways, roads and other infrastructure, they can cause a lot of disruption.
They commonly occur when the ground becomes saturated with water after long periods of heavy rain. As the earth becomes heavier, the water forces apart grains of soil so that they no longer lock together – resulting in a landslip as the structure becomes loose and unstable.
What we do when there’s a landslip
When landslips happen, unfortunately so do delays. A train can’t swerve to avoid debris on the line in the same way a car can avoid a small obstruction on the road, so when there‘s debris on the tracks after a landslip, we will often need to re-route services.
Before trains can run on the line again after a landslip, we’ll remove any debris and check that the infrastructure is safe and working.
There are ongoing concerns, even after an initial landslip. Once a landslip has started to move, the slope is permanently weakened. It means it’s much more likely that there will be further landslips. Some of the slopes – or cuttings, as they’re also known – on either side of our tracks need to be strengthened by improving drainage or adding stronger materials to the slope itself, such as steel rods or soil nails. This work to stabilise the earth can take time.
How we’re reducing delays caused by landslips
- It’s important that we identify the sites prone to landslips to ensure that we keep passengers and our engineers safe. We use helicopters equipped with laser imaging, detection and ranging to do this.
- Where we know that 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 not sufficient, we will then 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.