In a detailed press release issued on Saturday night, railways said during the transportation back from Varanasi it was stopped at Chamraula station of National Capital Region, about 18 kms after crossing Tundla station. "There was an issue of communication between the last basic unit of 4 coaches and the rest of the train probably due to some external hit. Thereafter, safety features in the train applied brakes. The train was checked for faults and moved to Delhi," it said.