Security expert Professor Stefan Katzenbeisser of Technische Universität Darmstadt told a security conference in Berlin that the GSM-R which is being installed in train networks makes them vulnerable to hackers.

Katzenbeisser said that the new system was vulnerable to “Denial of Service” attacks and, while trains could not crash, service could be disrupted for quite some time. Speaking to the Chaos Communication Congress he said that Network Rail is currently installing GSM-R across the British railway network.

It uses the similar technical standards to 2G mobile networks and is due to replace older signalling technology in southern England next year, and throughout the whole country in 2014. But train switching systems, which enable trains to be guided from one track to another at a railway junction, have historically been separate from the online world. If they were connected to the internet as they are in GSM-R they could be hit by Denial of Service attacks.

At the moment Britain trains can grind to a halt for things on the line ranging from frost, ice and leaves.