The railways on Sunday virtually ruled out driver error and system malfunction, indicating a possible “sabotage” and tampering of the electronic interlocking system behind the triple train accident that claimed at least 288 lives in Odisha. Railway Minister Ashwini Vaishnaw said the “root cause” of the accident and the “criminals” responsible for it have been identified. “It happened due to a change made in the electronic interlocking and point machine,” he told reporters at the site of the accident in Balasore district. Here in Delhi, top railway officials explained how the point machine and the interlocking system function. They said the system is “error proof” and “fail safe” but did not rule out the possibility of outside intervention.