Damaged knuckle decouples 18 coaches of TN train

CHENNAI After a coupler connecting S7 and S8 coaches of the Chennai-Coimbatore Cheran Express got detached due to a damaged knuckle, six coaches attached to the locomotive got unstuck leaving 18 coaches behind at Tiruvallur station on Saturday night. As the train was stopped immediately, a major accident was averted, sources said.