Rare solar storms could cause train accidents, scientists warn
Solar storms could cause chaos on the UK's rail network, with delays and even train accidents possible due to "powerful magnetic disturbances", scientists have warned.
Space weather is able to flip a red signal to green, researchers at Lancaster University have found - which they said was "very significant" for safety.
Lead researcher Cameron Patterson said space weather events capable of triggering faults are expected in the UK every few decades.
But Network Rail said the risk was "very small".
There are more than 50,000 signalling track circuits in the UK, where the signal is controlled by an electrical circuit between the rails.
Solar storms can trigger powerful magnetic disturbances on Earth, creating geomagnetically induced currents that can potentially interfere with electricity transmission.
Space weather can affect power grids and caused blackouts for millions in Quebec in 1989. In 1859, a massive solar eruption triggered a geomagnetic storm that disrupted telegraph lines across the world.
The team, led by Mr Patterson and Professor Jim Wild, modelled how the currents could cause rail signalling to malfunction.
"Crucially, our research suggests that space weather is able to flip a signal in either direction, turning a red signal green or a green signal red," Mr Patterson said.
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Mr Cameron has previously researched what are known as "right side" failures, where the signal is switched from green to red.
This is not dangerous - but the opposite "wrong side" failures, when the signal goes from red to green, are much more hazardous.
The new study, published in the journal Space Weather, found "wrong side" failures could happen at a lower geoelectric field strength than for "right side" failures
This means a weaker geomagnetic storm could more easily trigger "wrong side" failures.
Mr Cameron said: "Our research shows that space weather poses a serious, if relatively rare, risk to the rail signalling system, which could cause delays or even have more critical, safety implications.
"This natural hazard needs to be taken seriously. By their nature, high-impact, low-frequency events are hard to plan for, but ignoring them is rarely the best way forward."
Martin Frobisher, Network Rail's group safety and engineering director, told Sky News while solar storms were a "theoretical risk", the company considered it to be "very small".
"We need to focus our limited resources on higher priority issues such as climate change and security threats," he added.
