Rail accident investigators have issued an urgent warning over the reliability of landslide monitoring equipment on the UK's railways, following a serious derailment in Cumbria. The alert comes after sensors failed to detect a sudden landslip that forced an intercity train off the tracks.
The Shap Derailment: A Narrow Escape
On 3 November, an Avanti West Coast service travelling from Glasgow to London at 83 miles per hour struck debris washed onto the line by heavy rain near Shap, Cumbria. The impact caused the front wheels of the train to leave the rails. Fortunately, the train remained upright, averting a major disaster. Only four passengers sustained injuries in the incident.
The site at Shap is a known risk area during periods of high rainfall. Network Rail had installed remote earth movement monitoring equipment there to provide early warnings of potential landslides.
Sensor Failure During Critical Moment
The preliminary investigation by the Rail Accident Investigation Board (RAIB) revealed critical flaws in the monitoring system. Sensors closest to the landslide had detected minor earth movements in the railway cutting in the hours leading up to the accident. However, these movements were below the threshold that triggers an alert.
More alarmingly, the RAIB found that when the major landslip actually occurred, the sensors were tipped over too rapidly to register the movement. Furthermore, once buried under debris, the wireless signals from the sensors were unable to transmit any data.
The board's urgent safety warning to the rail industry states: “Line-side monitoring equipment used on Network Rail-managed infrastructure may not be able to detect the failure of slopes in some circumstances.” It emphasised that this equipment might not provide reliable data for safety decisions, particularly during extreme weather.
Broader Implications and Network Rail's Response
The RAIB has instructed Network Rail to “take urgent steps to consider and, if necessary, mitigate this risk.” The initial examination found that a drainage channel was overwhelmed by rainwater, saturating the earth in a cutting and triggering the landslide.
This incident echoes the UK's worst rail disaster in two decades, the 2020 Stonehaven derailment in Aberdeenshire, which was also caused by a landslide after heavy rain and resulted in three fatalities.
A Network Rail spokesperson said: “We have one of the safest railways in the world, and the safety of passengers and our colleagues remains our first priority.” The company acknowledged the increasing frequency of extreme weather and stated it is investing in new technology to monitor embankments and cuttings.
The company has committed to spending almost £100 million over the next four years on earthworks and drainage in north-west England alone to bolster the railway's resilience against adverse weather, as part of a wider effort to combat risks posed by the climate crisis.
