Space weather poses a risk to infrastructure in space and on the ground. Geomagnetically induced currents (GIC) are one of the foremost space weather hazards. During geomagnetic disturbances, fluctuating ionospheric currents produce changes to the magnetic fields observed at the Earth's surface. As described by Faraday's Law of Induction, this rapidly changing magnetic field drives electric currents in the Earth and through grounded conductors such as power transmission networks (

Studies of space weather impacts on ground-based infrastructure have been largely focused on power networks and pipelines, but railway signalling systems are also affected, with misoperations observed in several countries. This paper advances recent theoretical work on geomagnetically induced currents in railway signalling systems by modeling realistic railway lines with parameters from current industrial standards. Focusing on two example lines in the United Kingdom with different locations and orientation, a range of uniform electric fields are simulated along each modelled line. The results show that misoperations could be caused by geomagnetic interference at disturbance levels expected to recur over timescales of several decades. We also demonstrate that the UK estimate for the geoelectric field induced by a 1 in 100-year extreme storm would be strong enough to cause widespread signal misoperations in both lines studied.

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<p>Track circuits are widely used signalling systems that use electrical currents to detect the presence or absence of a train in predefined sections of a railway network, as such, they are susceptible to interference from geomagnetically induced currents.</p><p>This work aims to determine the impact space weather has on realistic track circuits across geologically different regions of the UK under various storm conditions by using the Spherical Elementary Current System method of geomagnetic field interpolation, a ground conductivity model of the UK, a 1D-layered model to provide estimations of the geoelectric field and track circuit modelling techniques developed by <em>Boteler (2021)</em>.</p><p>Early results of a modelled section of the West Coast Main Line in North West England will be presented.</p>

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