At least 7 people are feared killed in a major fire that broke out on two coaches of the Doon Express in the wee hours of today.The fire broke out in the AC-3-tier coaches, B1 and B2, when the train was passing through Nimiaghat station in Giridih district in Jharkhand.Though nothing official has come out about the fire, short circuit is being cited as the reason behind the fire.The train was on its way from Howrah to Dehradun.