C H A P T E R
N ° 19
Space Weather, The Rail Transport Sector, and Mitigation Measures
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 ‘C H A P T E R N ° 18 Space Weather and The Rail Transport Sector’, SR Hoplon introduced and discussed the relation between space weather and the railway sector through studies conducted in 2016 and 2024.
In today’s article, we will furtherly explore the relation between space weather and the railway transport sector. We will look closer at the creation of Geomagnetically Induced Currents (GICs) and its interaction with the Earth’s atmosphere. Additionally, we will discuss the interdependencies within critical infrastructure with a focus on the railway transport sector and the risks and vulnerabilities created from such dependencies. Lastly, a set of mitigation measures will be presented.
Image Credit: StockCake: An evening train ride under the aurora borealis.
Image Credit: NOAA: Cartoon illustrating the atmospheric layers of Earth.
Space Weather, Earth’s Atmospheric Layers, and Geomagnetically Induced Currents (GICs)
The critical national and global infrastructures are becoming increasingly dependent on technology. In addition, these same infrastructures are interdependent on each other. This dependency on technology and the interdependency internally creates a new set of vulnerabilities within each system and sector, and increases the risk of one of these systems, corporations, sectors etc. to experience issues, or total or minor collapse.
When discussing the relation between space weather and global and national critical infrastructures, these type of risks increases. Space weather is a term used to describe conditions - such as variations in the ionosphere, magnetosphere, or thermosphere - caused by the Sun when it interacts with other celestial bodies (Earth, the Moon, Mars etc.). These conditions can influence the performability and dependability of a variety of space and terrestrial (ground-based) engineering systems and human health (if at higher altitudes or in outer space) and safety.
The Earth’s atmospheric layer called the ‘ionosphere’ is a vital part of the atmosphere, as it can impact the movement of radio waves. The ionospheric layer can, thus, affect things such as telecommunication systems. As mentioned, space weather originates from solar activity (i.e., activities happening on the Sun) and emits optical and near-infrared radiation. During solar disturbances, Solar Energetic Particles (SEPs) gets released from the Sun. These particles have a high energy level and are magnetically and electrically charged which enables them to cause deviations across a range of wavelengths, such as Extreme Ultraviolet Radiation (EUV), X-Ray, and radio waves.
*The Ionosphere is within the atmospheric layer called the ‘thermosphere’. To learn more about the Earth’s atmospheric layers and space weather, please read: C H A P T E R N ° 11 Space weather and the Earth's atmospheric layers.*
During space weather events, the Solar Energetic Particles (SEPs) can affect currents of fluctuating intensity in the ionosphere and magnetosphere. The currents within the Solar Energetic Particles (SEPs) generate a magnetic field that stimulates a geoelectric field. These currents are known as ‘Geomagnetically Induced Currents’ (GICs) and can travel through the conductors within Earth and terrestrial (ground-based) technical networks. From previous articles published by SR Hoplon, we know that two of these networks and systems are electrical power grids and satellites. Others are oil, sewer and gas pipelines, and most importantly for today’s topic; railway systems.
*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.*
According to the American agency the National Oceanic and Atmospheric Administration (NOAA), ‘minor’ space weather events occur approximately 1700 times within an 11-year solar cycle, consequently influencing the space environment for a total of 900 days. More extreme events are argued to occur 4 times during one solar cycle, consequently leaving an effect for 4 days. Geomagnetically Induced Currents (GICs) and their effects are, thus, not uncommon.
*The 11-year solar cycle is the natural cycle of the Sun. During this period of time, the Sun transitions between low (i.e., solar minimum) and high (i.e., solar maximum) activity.*
The Railway infrastructures
Whilst the railway sector is susceptible to space weather impact, significant affects are mostly to occur during severe and extreme events. These types of events can cause direct and indirect effects on system components like; track circuits, electronic components in-build in signaling systems, or indirectly via interdependencies on electricity, communication etc.
While several space weather-related studies focused on power grids and space infrastructures like satellites have been conducted, a little has been done towards the investigation of probability of railway infrastructure disruptions. In blog ‘C H A P T E R N ° 19 Space Weather and The Rail Transport Sector’ we present and discuss some of the effects space weather can have on the rail transport sector. In the chapter the lack of awareness and research in this area compared to other sectors was mentioned.
Image Credit: Patrick Poend (shutterstock.com): An evening train ride under the aurora.
We know that the railway transport sector depends on the availability of other critical infrastructures like power, signaling, communications, and navigation systems for operations and positioning. Yet one part that has been left untouched in the discussion of the railway sector is digitalized railways. These depend on advancements like digitalization, cloud storage, big data, maintenance 4.0, Internet of Things (IoT), and cyber-physical systems that can all be affected by space weather. Moreover, space weather could potentially disrupt digital electronic equipment’s within the vehicles themselves. The investigations and understanding of this area and its overall consequences for the railway infrastructure is limited.
*Internet of Things (IoT) refers to the network of physical objects (i.e., things) that are embedded with sensors, software, and other technologies for the purpose of connecting and exchanging data with other devices and systems over the internet.*
These types of technological advancements have increased our critical infrastructure’s vulnerability to space weather impact. The previous generations of trains - such as the steam trains – were not exposed or affected by spacer weather events. However, the current electric trains have shown a certain level of susceptibility. For example; the insufficiency of isolating components within the modern trains causes the chance for reversing back additional currents into railway signaling systems from the track circuits. This is similar to the currents that destabilizes power grids in the event of severe and extreme space weather events. Areas such as this need more research before all electric trains gets fully automated or more advanced.
The railway sector’s dependency on the energy sector is likewise a critical vulnerability, due to its immediate impact on the railway network. Furthermore, power failures can, additionally, affect other system in the stations. At the stations, the most safety critical significant system vulnerable to space weather impact in the form of Geomagnetically Induced Currents (GICs) are the signaling and traffic control systems. This is due to the lengths of track-circuit and longer length of trains. Other issues are the changes in the flow of the currents, equipment such as heating systems, wayside cables, telecommunication and line-side circuits, backup systems, batteries, condition monitoring systems, point circuits in switching and crossings, and location cabinets.
Communication is a large part of the safety and functioning of the railway system. However, most advanced train control technologies like European Train Control System (ETCS) and European Railway Traffic Management System (ERTMS) are dependent on communication channels using mobile phone and wireless technology. The communication channels facilitate trains to transmit their speed and position to control centers, which then uses the same systems to communicate movement to trains. This operating system is highly susceptible to interference from space weather.
The interference from space weather could cause a loss in communication, consequently leading to halting movement of railways and disruption to railway schedules. These are, however, only some of the known affects. As discussed in SR Hoplon’s previous blog article, the impact of space weather, additionally, increase the systems vulnerability and likelihood of fatal consequences if not mitigated. This is especially when looking at the effect of space weather on the railway signaling system and its dependency on the Global Navigation Satellite System (GNSS) providing position, navigation, and timing data.
The railway infrastructure is highly dependent on the Global Navigation Satellite System (GNSS). However, satellites are the most at risk critical space infrastructure to space weather impact, as it can influence the functioning of the satellites, the quality of the data they transmit, and the user’s capability to collect the transmitted signals. A space weather impact on the Global Navigation Satellite System (GNSS) can lead to an influence on the registered position and tracking of trains. Although, this is not the main concern, as the Global Navigation Satellite System (GNSS) is not the main technology utilized for this function due to tunnels. However, various location-dependent functions like controlling speed, detection of landslip and maintenance strongly depend on the Global Positioning System (GPS), which is a part of the Global Navigation Satellite System (GNSS).
*To learn more about satellites and space weather, please read: C H A P T E R N ° 9 Space weather and Satellites.*
Furthermore, space weather can, additionally, cause damage to the train itself. A possible effect is, for example, the risk of corrosion on components on the train, due to the induced electric currents caused by space weather. Moreover, studies have shown that space weather can interfere with a train’s bearings.
*Bearings are a part of a train that provide support to the rotating parts of the locomotive, such as the axles and wheelsets, and help distribute the load evenly.*
Bearings are generally in a rotational mode, and as electric currents travel all the way through a bearing, it can cause arcing and burning on the thin oil film located at joints of contact between the raceway and rolling elements. The Geomagnetically Induced Currents (GICs) can change the characteristics of the component, and electromagnetic interference can cause faults and failures. This has already been experienced on the Swedish Railway. The lifetime of the bearings may, thus, be reduced, due to the sudden accumulation of stresses.
Mitigation Measures
Throughout the years, some nations have begun to address the risks associated with space weather. Additionally, forecasting and early warning systems have been created and implemented. Yet, there is still a need for investigations on mitigation procedures and operations, and mitigation cooperation. Some of the discussed mitigation measures throughout time are as followed:
Awareness and research of space weather should be increased within the rail transport sector, and forecasting and early warning systems need to be implemented. The integration of forecasting and awareness through the international forum of electricity distribution grids could decrease the risks posed by space weather and help with the creation and implementation of operational mitigation strategies. Moreover, it would help to implement emergency and contingency plans in case of severe or extreme space weather events.
Furthermore, developers and prospective users of the railway system need to invest in innovative solutions focused on design and manufacturing in order to reduce the long-term impacts of space weather on the railway infrastructure. The economic costs associated with the creation and implementation of mitigation measures have shown to be moderate compared to the impact from a single event - this does, however, depend on country, systems used etc.
Mitigation measures such as; inserting a real-time Geomagnetically Induced Current (GIC) observer for every susceptible transformer with methods to cut down Alternating Current (AC) power whenever necessary to prevent permanent destruction; exploiting digital relays to prevent false tripping after Geomagnetically Induced Current (GIC) harmonics; and adding neutral-current-blocking-capacitors (NCBCs) together with shunt protection could be three ways to minimize the impact of space weather.
*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.*
Other mitigation measures mentioned in different studies are the implementation of control of differential mode voltage in order to lessen the interference to the track circuits, and also to reduce the voltage in rail to rail. Additionally, it could help to insulate joints, impedance bonds, surge arrestors, and ballast maintenance as a part of the railway maintenance. Lastly, an implementation of proactive procedures to observe the internal temperature of the oil in transformers, and the monitorization of harmonic content using condition monitoring techniques of their power grids to find out when changes are happening could likewise be implement.
Image Credit: Alaska By Design: An evening train ride under the aurora.
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