The locomotive of the 5959-Up Kamrup Express was damaged in an explosion triggered by suspected tribal Karbi militants at Khakhati in Assam's Karbi Anglong district on Tuesday.
Over 400 passengers were present in the train at the time of the blast, but no injuries were reported.
A Northeast Frontier Railway spokesman said the damaged locomotive was replaced and the train resumed its journey towards Tinsukia in Eastern Assam. The Kamrup Express runs daily between Howrah in Kolkata and Tinsukia in eastern Assam.