Solar Storm Effects on Rail Systems
Who would've thought charged particles from the sun could pose a threat to our train signaling systems? Yet, a recent study conducted by British and Canadian scientists reveals this unexpected danger[^1^]. Even minor solar storms, which occur about once every ten to twenty years, can alter railroad signals from red to green, posing a risk of collisions[^1^].
The study, published in the journal "Space Weather," highlights that these alterations happen due to track vacancy detection systems. These systems are part of a circuit that includes the rails. Solar storms can generate geomagnetically induced currents, which could affect this circuit and lead to signals changing colors[^1^].
In the UK, modern track vacancy detection systems are less sensitive to disturbances caused by solar storms. However, older, more vulnerable systems are still common[^1^]. In these older systems, the track is divided into blocks. A relay located at the beginning of a block, which receives power from a source at the end, checks for trains. If no train is detected, the circuit is closed, and the signal shows "green." If a train is present, it creates a short circuit, causing the signal to shift to "red"[^1^].
The researchers from Lancaster University tested this concept by recreating track vacancy detection systems on sections of British and Scottish railways in a computer model. They simulated electrical voltages like those triggered by solar storms and discovered that individual systems can be disrupted by just 1.1 volts per kilometer in West Lancashire and 1 volt per kilometer in Scotland[^1^]. Such low voltages can cause track signals to change, potentially leading to collisions[^1^].
Though Sweden faced such incidents in July 1982, where a signal switched colors during a geomagnetic storm without any trains in the line, this phenomenon is quite rare[^1^]. Still, space weather forecasts could potentially help mitigate risks during an extreme event[^1^].
[^1^]: ntv.de
Additional Insights
Solar storms can have several other impacts on train operations, including:
- Electromagnetic Interference (EMI): Strong electromagnetic fields generated by solar storms can interfere with electronic systems used in train signaling, causing malfunctions, errors, or complete system failures[^2^][^3^].
- Power Grid Disruptions: Solar storms can potentially cause power grid disruptions, impacting electricity supply to train stations and signaling systems, resulting in signal failures, delays, or even the shutdown of entire rail systems[^2^].
To mitigate these risks during a solar storm, several measures can be taken, including advanced power flow controls, redundancy and backup systems, real-time monitoring, standardized emergency protocols, and infrastructure resilience[^2^].
