Solar storms not only threaten satellites, they could also disrupt critical infrastructure on Earth, such as railway networks. In a study relayed by New Scientist, researcher Cameron Patterson, from Lancaster University in the United Kingdom, believes that certain electrical systems used in railways are vulnerable to these phenomena, with potentially serious consequences.
The main risk concerns signaling systems, essential to train safety. In the worst case, a red signal could be interpreted as green, paving the way for a collision. “Disruptions to signaling could occur, and it is crucial to prepare for them now”alerts the researcher.
At the origin of these disturbances is the activity of the Sun. This constantly emits a flow of charged particles, called solar wind, responsible in particular for the Northern Lights. But during more intense episodes, called solar storms, increased amounts of matter and energy are thrown toward Earth, affecting its magnetic field.
These variations in the magnetic field can induce unexpected electric currents on the surface of the globe. Geomagnetically induced currents that can flow through conductive infrastructure, such as railway tracks, and disrupt their operation. However, many railway networks rely on electrical circuits integrated into the tracks to detect the presence of trains. The passage of a train modifies the current in a section of rail, which allows you to know if the track is occupied. The introduction of parasitic currents can therefore distort these measurements.
In this context, anomalies become possible: a signal supposed to be red can turn green, or vice versa. If a train travels at high speed without reliable warning, there may be insufficient reaction time to avoid an accident. Even less critical disruptions, such as a green signal turning red, can cause sudden stops and dangerous situations for passengers.
Anomalies that are difficult to spot
This is what happened in July 1982 in Sweden, when signaling anomalies were directly linked to a solar storm. However, according to Cameron Patterson, this type of event could be largely underestimated. Engineers, once on site, often do not notice any apparent failure, because the effects disappear with the storm, which complicates their identification.
Beyond signaling, other components of rail networks could be affected, such as transformers supplying power lines, radio communication systems, devices allowing trains to tilt on turns at high speed or even satellite geolocation systems. All of these technologies depend, to varying degrees, on electrical signals sensitive to disturbances.
The overall risk remains relatively low: solar storms powerful enough to cause this type of disturbance only occur on average once every thirty years. But rarer and more intense events that could lead to massive outages remain possible at any time.
Faced with this threat, work is underway to strengthen the resilience of infrastructure. Cameron Patterson is working in particular with rail stakeholders in the United Kingdom to anticipate these risks and adapt existing systems.
