Attal said “ nerve centers ” were targeted, suggesting “ a certain knowledge of the network.” It was not immediately clear who was behind the suspected attacks and authorities did not announce any arrests.... It’s very delicate work.” Before railway traffic can resume, Farandou said, all repaired signals will need to be tested.... It advised travelers to postpone their trips and said a quarter of its train routes had been canceled through the weekend.“ At this stage, it is probably one or seve