C H A P T E R
N ° 18
Space Weather and The Rail Transport Sector
Space weather is a natural hazard comprising a wide range of phenomena. These phenomena can cause different types of effects on critical national and global infrastructures. In reason years, investigations have been made on a range of sectors to increase understanding and awareness of this natural hazard’s impact.
In today’s article, we will explore the relation between space weather and the rail transport sector. We will look closer at how and in what way space weather effects this sector and discuss studies exploring the potential risk and vulnerabilities of impact of space weather on the rail transport sector.
Image Credit: Advancing Earth and Space Sciences (AGU).
Geomagnetically Induced Currents (GICs)
Space weather can affect the rail transport sector in two ways. It can either impact it directly or indirectly. An example of a direct impact is Geomagnetically Induced Currents (GICs) in transformers or rail tracks, whereas indirect effects are caused through the rail transport sectors dependency on other critical infrastructures which are also vulnerable to space weather impact. Such sectors are the energy sector and the space sector, due to a need for electricity and dependencies on communication and Global Navigation Satellites System (GNSS) services.
*Geomagnetically Induced Currents (GICs) are electrical currents induced at the Earth’s surface by rapid changes in the geomagnetic field due to space weather impact.*
Space weather impact on the rail transport sector has been documented in several countries such as in Sweden, Russia, and the United Kingdom. It can cause issues such as signaling system misoperations, damage to locomotive on-board transformers, and issues related to its dependency on other critical infrastructures. However, disruptions to signaling appears to be the primary effect.
The 2016 Atkins and The 2024 Lancaster University space weather and railway studies
In 2016, the advisory company Atkins (specialized in things like railways) carried out an initial study with the assumption that a space weather event had already occurred. The study was conducted in order to better understand the vulnerability of the United Kingdom’s (UK’s) rail network to extreme space weather and its impact on safety and operability.
In recent years (2024) a similar investigation was conducted by Dr. Cameron Patterson and Professor Jim Wild from Lancaster University in the UK on the impact of space weather on Alternating Current (AC) electrified rail lines.
*Alternating Current (AC) is the type of electrical current in which the current repeatedly changes direction. The vast majority of power plants and power distribution systems use this type of current, as it is easier to generate and the transmission leads to lower energy losses than Direct Currents (DC) over distances more than a few meters.*
In both studies, the investigations highlighted a strong susceptibility of rail assets in the UK to space weather impact due to direct impacts on the infrastructure, and indirectly through its dependency on power, the Global Navigation Satellites System (GNSS), and radio communication. The studies revealed that solar storms capable of triggering Geomagnetically Induced Currents (GICs) could lead to malfunctions in rail signaling. A malfunction in rail signals could potentially lead to accidents if not mitigated.
Solar storms can create powerful magnetic disturbances on Earth, generating Geomagnetically Induced Currents (GICs) that can interfere with electricity transmission and distribution grids.
The studies conducted by Atkins and Lancaster University explains that there is a theoretical risk that Geomagnetically Induced Currents (GICs) that is induced or directly coupled into rail may lead to wrong-side failures, which raises strong safety concerns.
Image Credit: International Journal of System Assurance Engineering and Management Article “Space weather climate impacts on railway infrastructure” figure 3: Change of signals due to presence of wheel
According to the studies, space weather can cause transformers to fail and is able to flip signals in either direction, consequently turning a red signal to a green signal or vice versa. This is because Geomagnetically Induced Currents (GICs) can enter rail equipment like rolling-stock transformers and track-circuit feed transformers and interfere with their systems. A switch from a green to a red signal – also called a “right side” failure – would not cause much harm as trains would most likely stop operating. However, if a red signal turns into a green (i.e., “wrong side” failure) the consequences would be different. The possibility and risk of a “wrong side” failure has shown to be much higher than assumed, as this type of failure could occur even during lower geomagnetic storms.
On the railway lines studied, “right side” failures are expected to arise from events that occur approximately once every 30 years, whereas ‘wrong side’ failures have the potential to arise from events occurring approximately once every 10-20 years. Space weather events are, thus, capable of causing faults in track circuits every few decades. Additionally, the research showed that extreme events have the potential to cause very significant signaling disruption on the lines studied - most of them on the ‘wrong side’ - which makes it safety critical.
Furthermore, the study conducted by Atkins explains that line current monitoring equipment may interpret the quasi-Direct Current (DC) Geomagnetically Induced Currents (GICs) as incorrect train operation, consequently leading to a shutdown of trains. A similar outcome could happen due to the rail sectors dependency on the energy sector.
*Direct Current (DC) is electrical current which flows consistently in one direction. The current that flows in a flashlight or another appliance running on batteries is direct current. *
Space weather impact on the energy sector - such as issues with power grid systems leading to power outages - would indirectly affect train operations. With train batteries lasting no longer than 90-120 minutes, issues would arise within signaling and services at train stations, including lighting. In this context, the Atkin study highlights a concern about self-evacuation and panic behaviour with passengers stranded in trains or blocked at stations.
The potential space weather impact on and failure of the Global Navigation Satellite System (GNSS) was not identified as a safety concern during the Atkins 2016 investigation. However, the Global Positioning System (GPS) – a service provided by the Global Navigation Satellite System (GNSS) - plays a key role in maintaining timing on the Global System for Mobile Communication (GSM-R12) network, as well as in the line-side telecommunications system. The Global Positioning System (GPS) is also used for Selective Door Opening to determine the location of the train on the rail network, and for supporting the train’s propulsion system.
The Atkins study does, however, indicate that radio communication that uses directional antennas, such as Global System for Mobile Communication (GSM-R), would only be disrupted during sunrise and sunset. However, their loss could be critical during emergencies.
Lastly, an interesting finding from the 2016 Atkins study was, that there seems to be a risk to track-side staff during extreme space weather, due to the unexpected activation of protection systems by Geomagnetically Induced Currents (GICs) in conductors. This was, however, not investigated during the study from Lancaster University conducted in 2024.
Image Credit: Norwegian Travel: Northern Light (Aurora) above Norwegian train in Narvik.
Rail sector risk
Severe space weather is getting increasingly more recognized as a significant risk to the rail transport sector. The research conducted by universities and companies like Atkins and Lancaster University underscores the importance of the rail sector being included in planning for mitigating risks associated with space weather. Like other sectors, the rail transport sector must be proactive in ensuring the safety of its operations considering the natural hazard.
The Atkins study provides recommendations for research, forecasting and warning, and monitoring and measuring. Furthermore, it recommends to close existing knowledge gaps, while at the same time considering the potential for multiple and simultaneous impacts. The knowledge gaps could be related to single-event effects, track-circuit interference, and Global Navigation Satellite System (GNSS) dependencies. In addition to the recommendations by Atkins, a mitigation measure suggested by Professor Jim Wild and Dr. Cameron Patterson is to integrate space weather forecasting into the decision-making processes in order to know when to limit railway operations during extreme events.
Most importantly, the studies suggest a strong need for collaboration and communication among industries and between industry and academia.
Source
Krausmann, Elisabeth et al. (2016): “Space weather and critical infrastructures: Findings and Outlook”.European Commission, JRC Science For Policy Report. DOI: 10.2788/152877
Met Office (n.d.): “Space Weather Impacts”. https://www.metoffice.gov.uk/weather/learn-about/space-weather/impacts
Patterson, C.J.; Wild, J.A.; Beggan, C.D. et al. (2024): “Modelling electrified railway signalling misoperations during extreme space weather events in the UK”. Sci. Rep., No. 14. Pp 1583. DOI: https://doi.org/10.1038/s41598-024-51390-3
Thaduri, A.; Galar, D.; Kumar, U. (2020): “Space weather climate impacts on railway infrastructure”. Int J Syst Assur Eng Manag 11 (Suppl 2). Pp 267–281. DOI: https://doi.org/10.1007/s13198-020-01003-9
