The train, with around 1000 passengers, mostly pilgrims bound for Puri left Guwahati railway station at 5:40 pm, railway officials said.
According to the local residents, they had heard a deafening sound just before the derailment. It is being suspected that a faction of the National Democratic Front of Bodoland (NDFB) might be behind the blast.
Around 8:30 pm an explosion at Dhatkuchi between Rangia and Ghagrapar led to the derailment of the engine and the four bogies immediately behind it but they remained standing, while four other bogies capsized and fell into a water-filled ditch.
Most of the victims were rushed to Rangiya district hospital, though it is being suspected that many more are still trapped inside the bogies.
"We had eight bogies derailing out of which four remained standing, but fortunately there has been no casualty what so ever, there have been some injuries and we have been able to attend to them," Suresh Chandra, GM N F Railways said.
This accident took place hours after the derailment of Delhi bound Kalka Express in Uttar Pradesh.