German rail operator Deutsche Bahn said on Saturday that an act of “sabotage” against its communications cables caused massive problems with the train network in the north of the country for several hours in the morning. The damage to fibre optic cables took place in two locations, security sources told dpa: in Berlin’s Hohenschönhausen district and an the city of Herne in the western state of North Rhine Westphalia. “Cables that are essential for train operations were maliciously and wilfully cut,” German Transport Minister Volker Wissing said. Security authorities had taken over the investig…