Fire Service and Civil Defence director (operation and maintenance) Lt Col Tajul Islam Chowdhury said that initially it seems 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 will 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 fire in three bogies and then spread to the fourth bogey."
A total of eight units are working to control the fire.
He added that the death toll could rise after the rescue operation was completed.