(ORDO NEWS) — Space weather fluctuations disrupt rail systems and cause significant train delays. A project investigating the effects of solar storms on railroad signals will be presented this week at the National Astronomy Meeting (NAM 2022) by Cameron Patterson, a PhD student at Lancaster University.
The Sun‘s ability to influence technology on Earth as well as in space is known as space weather. On railroads, electrical currents caused by solar activity can disrupt signals, turning a green signal into red, even if there is no train nearby.
Patterson says: “Most of us have heard the dreadful words, ‘Your train is being delayed because of a malfunction in the signaling system’, and although we usually associate these malfunctions with rain, snow and leaves on the line, you may not have thought about that the Sun can also cause railroad signals to malfunction.”
To track the location of trains, the railway line is divided into small consecutive segments, called “blocks”, the average length of which is 1-2 km. Each block is associated with a signal that tells if a train is currently in that block.
The signals are controlled by relays that detect currents in the system. Synonymous with traffic lights: the signals turn green if the block is empty and current is detected, or red if the block is busy and no current is detected.
Solar storms can upset the balance of currents that drive light signals on rail lines, causing traffic lights to show vacant sections as occupied by red light. Evidence shows that stronger solar storms cause more signals to fail, thus increasing train delays.
A team of researchers from Lancaster University have modeled the effects of solar storms on two sections of the UK rail network: the South-North line from Preston to Lancaster and the West-East line from Glasgow to Edinburgh.
Technological problems can arise as a result of solar storms of various strengths: from medium storms with an electric field strength of 2 V/km to strong storms with an intensity of 4 V/km.
In the past, values over 7 V/km have been found along railways in Sweden. Estimates of extreme solar storms predicted events with intensity up to 20 V/km.
Interestingly, the results show that signal failures can occur even during moderate storms. So while these estimates are worrisome, there is still cause for concern without these extreme storms.
Describing the future of his work, Patterson says: “We are now working to look at the case where trains are on the line and determine how strong a storm would need to be for the red signal to turn green again – a much more dangerous scenario that could lead to accidents!”
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