A major train tragedy was averted on Friday when a bomb planted on railway tracks by suspected tribal militants in lower Assam's Udalguri district exploded minutes after Arunachal Express passed the area, official sources said.

The sources said suspected Adivasi National Liberation Army militants had planted the bomb on the metre gauge track of the Northeast Frontier Railway between Harisinga and Rangapara on Friday night targeting Arunachal Express.

But the bomb exploded around 8.15 pm just after the train passed the area damaging the railway tracks and disrupting train services, they said.

Wire and batteries were recoverd from the spot, the sources said, adding senior railway and police officers had rushed to the spot.