A professor at Technische Universitat Darmstadt in Germany has claimed to discovered a vulnerability that could cause massive trouble for rail networks. Prof Stefan Katzenbeisser said the vulnerability, he pinpointed, is due to mobile phone signals used to link railway switching systems together that would allow hackers to cause massive service disruption. the use of "connected" systems allowed this vulnerability to be but he stated "Trains could not crash, but service could be disrupted for quite some time,". According to Prof Katzenbeisser, 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, but communication between trains and switches is handled increasingly using wireless technology. Source