Rail industry urged to consider safety risks of space weather

Train accidents could be caused by solar storms that change signals from red to green, according to new research examining the impact of space weather.

Solar storms can trigger powerful magnetic disturbances on Earth, creating geomagnetically induced currents (GICs) that could potentially interfere with electricity transmission and distribution networks.

A team led by Ph.D. Researcher Cameron Patterson and Professor Jim Wild from Lancaster University modeled how GICs flowed through the circuits of electrified AC lines fed by overhead wires.

Using two routes (the Preston to Lancaster section of the West Coast Main Line and the Glasgow to Edinburgh line), the team modeled how GICs induced in the rails could cause railway signaling to malfunction.

There are over 50,000 signaling circuits in the UK, where the signal is controlled by an electrical circuit between the rails.

PhD in Physics. Researcher Cameron Patterson said: “Most importantly, our research suggests that space weather is capable of reversing a signal in either direction, turning a red signal into green or a green signal into red. This is obviously very important from a perspective. of security.

“By building a computer model of the track signaling circuits using realistic specifications for the various components of the system, we discovered that space weather events capable of causing failures in these track circuits are expected in the UK every few decades.”

Cameron’s previous research in the magazine. Space weather explored what is known in the industry as “right-side” faults, where the signal changes from green to red.

This is a fail-safe scenario, but reverse “wrong side” failures (when the signal goes from red to green) are much more dangerous.

This last study, also in Space weathershows that “wrong side” faults could occur at a lower geoelectric field intensity than “right side” faults, meaning that a weaker geomagnetic storm could more easily trigger “wrong side” faults.

It was estimated that, on the studied lines, “wrong side” failures could occur due to a geomagnetic storm with a frequency of approximately one to two decades.

The analysis was also performed for a once-in-a-century extreme event, and it was shown that it could cause many malfunctions of both types on lines in both directions of travel, depending on the number of trains on the line at that time. . time.

Cameron said: “When we experience severe space weather that occurs every few decades or extreme space weather that is observed every century or two, there is the potential for significant signaling malfunctions, which has an obvious impact on safety”.

There have been several examples of space weather impacting power grids in recent decades, including power outages that affected millions of people in the Canadian province of Quebec in 1989 and in the Swedish city of Malmo in 2003.

There are also historical examples of space weather interference with railway signaling dating back to the 19th century. And in 1859, a massive solar flare triggered a geomagnetic storm that disrupted telegraph lines around the world. The team also evaluated the impact of a solar storm the size of the 1859 event, predicting that it would cause widespread problems with signaling on both lines studied.

Cameron said: “Our research shows that space weather represents a serious, although relatively rare, risk to the railway signaling system, which could cause delays or even have more critical safety implications. This natural hazard must be taken seriously. Therefore nature “It’s difficult to plan for high-impact, low-frequency events, but ignoring them is rarely the best way forward.”

Jim Wild, Professor of Space Physics at Lancaster University, said: “Other industries such as aviation, electricity generation and transmission and the space sector are considering the risks to their operations and exploring how they could be mitigated. It is important that the sector railway is included in this planning.”

“As our understanding of the space weather hazard improves, we may consider how to reduce the risks. In the future, we could see the space weather forecast being used to make decisions about limiting rail operations if an event is expected. extreme, as are weather forecasts. Forecasts are currently used.”

Severe space weather is listed on the UK government’s National Risk Register for Civil Emergencies, which lists the risk it poses to the UK economy and society as “significant”.