"I am not excluding anything. I got a call from the Divisional Railway Manager that there was a report of a blast. I don't want to dwell on it further since you will infer that I am trying to divert the cause of the mishap to another direction," Mr Roy told reporters in Kolkata fore leaving for the accident site.
Later, he told PTI, "Some of the injured passengers admitted to hospitals and a gateman at one of the level crossings near Nellore station heard a loud sound when the fire occurred in the coach."
Asked if he suspected sabotage, he said, "I am not saying anything at this stage."
"Nothing is being ruled out and nothing can be said without an investigation. It will be investigated if inflammable substances were kept in the compartment or the fire was caused by a short circuit," the minister said.
Mr Roy said he had ordered an inquiry into the fire.
Mr Roy said he had spoken to the Railway Board for setting up a high-power committee which would investigate the cause of the fire.
Describing the incident as "very tragic and unfortunate", the minister announced an ex-gratia payment of Rs 5 lakh to the next of kin of each killed, besides a job.
He said Rs one lakh each would also be paid to those with grievous injuries and Rs 25,000 for those with minor injuries.