Space weather will delay your trains

The image shows the Earth and Sun in space, with the Earth surrounded by purple hued radiation belts.
An illustration of the Sun interacting with Earth’s magnetosphere.
NASA's Goddard Space Flight Center/Mary Pat Hrybyk-Keith

Fluctuations in space weather are disrupting train signals and causing significant delays. A project investigating the effect of solar storms on railway 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 tendency to affect technology on Earth, as well as in space, is known as space weather. In railways, electric currents caused to flow in the earth by solar activity can interfere with the normal operation of signals, turning green signals to red even when there is no train nearby.

Patterson says: “Most of us have at one point heard the dreaded words: ‘your train is delayed due to a signalling failure’, and while we usually connect these faults to rain, snow and leaves on the line, you may not have considered that the Sun can also cause railway signals to malfunction.”

To track the location of trains, a railway line is split into small, consecutive segments called ‘blocks’ with an average length of 1-2 km. Each block is tied to a signal that tells you if there is a train currently in that block. The signals are controlled by relays which detect currents in the system. Synonymous to traffic lights, the signals turn green if the block is empty and a current is detected, or red if the block is occupied and no current is detected.

Solar storms can off-set the balance of currents controlling the light signals on train lines, causing lights to show clear sections as occupied with a red light. Evidence shows that stronger solar storms cause more signals to malfunction, thus increasing the amount time the train is delayed.

A team of researchers at the University of Lancaster have modelled the impacts of solar storms on two segments of the UK railway network: a South-North line from Preston to Lancaster and a West-East line from Glasgow to Edinburgh.

Technological problems can occur as a result of solar storms with a range of strengths: from medium storms with electric field strengths of 2V/km to strong storms at 4V/km. In the past, values of higher than 7 V/km have been detected along railways in Sweden. Estimates of extreme solar storms have predicted events with strengths of up to 20 V/km.

Interestingly, the results suggest that signalling failures can occur even with moderate storms. So, while these estimates are unsettling, there is still cause for concern without these extreme storms.

Describing the future of his work, Patterson says: “We are now working on looking at the case where trains are present on the line, and how strong a storm needs to be to turn a red signal back to green - a far more hazardous scenario potentially leading to crashes!”

Media contacts

Dr Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7292 3979
Mob: +44 (0)7802 877 699

Ms Gurjeet Kahlon
Royal Astronomical Society
Mob: +44 (0)7802 877700

Ms Cait Cullen
Royal Astronomical Society

Science contacts

Cameron Patterson
Lancaster University

Professor James Wild
Lancaster University

Images and Captions

Image link:
Caption:An illustration of the Sun interacting with Earth’s magnetosphere.
Credit: NASA's Goddard Space Flight Center/Mary Pat Hrybyk-Keith
Image link:
Caption: A geographic map of part of the United Kingdom showing railway lines being studied. The top line (blue) is the Glasgow to Edinburgh line, stretching in an west-east orientation; the bottom line (red) is a portion of the West Coast Main Line from Preston to Lancaster, with the extension beyond those sections displayed opaquely, stretching in a south-north orientation. The location of railway signals are shown as dots.
Credit: C. J. Patterson, “Geographic map of UK railway lines with signal locations”, 2022

Notes for editors

About NAM 2022

The NAM 2022 conference is principally sponsored by the Royal Astronomical Society (RAS), the Science and Technology Facilities Council (STFC) and the University of Warwick.

About the Royal Astronomical Society

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

Follow the RAS on Twitter, Facebook, Instagram and YouTube.

About the Science and Technology Facilities Council

The Science and Technology Facilities Council (STFC) is part of UK Research and Innovation – the UK body which works in partnership with universities, research organisations, businesses, charities, and government to create the best possible environment for research and innovation to flourish. STFC funds and supports research in particle and nuclear physics, astronomy, gravitational research and astrophysics, and space science and also operates a network of five national laboratories, including the Rutherford Appleton Laboratory and the Daresbury Laboratory, as well as supporting UK research at a number of international research facilities including CERN, FERMILAB, the ESO telescopes in Chile and many more.

STFC's Astronomy and Space Science programme provides support for a wide range of facilities, research groups and individuals in order to investigate some of the highest priority questions in astrophysics, cosmology and solar system science. STFC's astronomy and space science programme is delivered through grant funding for research activities, and also through support of technical activities at STFC's UK Astronomy Technology Centre and RAL Space at the Rutherford Appleton Laboratory. STFC also supports UK astronomy through the international European Southern Observatory and the Square Kilometre Array Organisation.

Visit for more information.

Follow STFC on Twitter: @STFC_Matters

About the University of Warwick

The University of Warwick is one of the world’s leading research institutions, ranked in the UK’s top 10 and world top 80 universities. Since its foundation in 1965 Warwick has established a reputation of scientific excellence, through the Faculty of Science, Engineering and Medicine (which includes WMG and the Warwick Medical School).

Submitted by Gurjeet Kahlon on Wed, 13/07/2022 - 17:57