An unidentified teenager, described as his teachers as a model student and an electronics genius, hacked a TV remote control so it control the Polish tram system like a "giant train set":
Miroslaw Micor, a spokesman for Lodz police, said: "He studied the trams and the tracks for a long time and then built a device that looked like a TV remote control and used it to manoeuvre the trams and the tracks.
"He had converted the television control into a device capable of controlling all the junctions on the line and wrote in the pages of a school exercise book where the best junctions were to move trams around and what signals to change.
"He treated it like any other schoolboy might a giant train set, but it was lucky nobody was killed. Four trams were derailed, and others had to make emergency stops that left passengers hurt. He clearly did not think about the consequences of his actions."