Rail signalling at risk from space weather

Examining two routes - the Preston to Lancaster section of the West Coast Main Line, and the Glasgow to Edinburgh line – the research modelled the effect of geomagnetically induced currents (GICs) caused by powerful solar storms. It was found that GICs flowed through the track circuits of AC electrified lines powered with overhead cables, potentially switching rail signals from red to green and vice versa. The work is published in Space Weather.

“Crucially, our research suggests that space weather is able to flip a signal in either direction, turning a red signal green or a green signal red,” said Lancaster University physics PhD researcher Cameron Patterson. “This is obviously very significant from a safety perspective.

“By building a computer model of the signalling track circuits using realistic specifications for the various components of the system, we found that space weather events capable of triggering faults in these track circuits are expected in the UK every few decades.”