Fire Service and Civil Defence Director (operation and maintenance) Lt Col Tajul Islam Chowdhury said that initially, it seemed miscreants or an electric short circuit might have been the cause of the fire on the Benapole Express.
He also said the cause of the fire would be ascertained after investigation.
"The Benapole Express train left Benapole and was coming to Kamalapur Station via Padma Bridge. On the way, three bogies caught fire while crossing the Gopibagh Bank area," he added.
In response to a question, he said: "We have come to know that the fire first caught in three bogies and then spread to the fourth bogey."
He added that the death toll could rise after the rescue operation was completed.