AMBALA, May 19: An alert railway employee today averted a major railway accident when he signalled train to stop short ahead of a cracked railway track at Sambhu,about 3 km from Ambala City. A gangman who looks after the maintenance of railway lines rushed to caution the driver of the train, railway sources said adding that the railway driver managed to stop the train between Sambhu and Ambala City. The intercity express was delayed by half an hour while Amritsar Shatabadi Express departed late by half an hour.