The passengers were found unconscious when the train stopped at the railway station here.
They were taken to Burdwan Medical College and Hospital when other passengers of the compartment of the train from Delhi spotted them lying unconscious and informed the GRP, the official said.
Of the five passengers, three regained consciousness and spoke to the police. According to them, they could not remember anything after some unknown persons offered them tea and cold drinks near Kanpur, the official said.