>>Because the trains use a radio system that lacks encryption or authentication for those commands, Olejnik says, anyone with as little as $30 of off-the-shelf radio equipment can broadcast the command to a Polish train—sending a series of three acoustic tones at a 150.100 megahertz frequency—and trigger their emergency stop function.<p>Goes without saying here that this needs to be fixed ASAP.<p>>>The railway agency wrote that “there is no threat to rail passengers. The result of this event is only difficulties in the running of trains.”<p>There is no threat to rail passengers, unless a passenger train does not know about a stopped train ahead of it on the tracks, e.g., a cargo train go stopped by the hack, but the passenger train 10min behind it did not and continues to rush onward towards the stopped cargo train. IDK if Poland's control system would reliably detects these conditions, but if it does not with 100% reliability, this is a real threat.