Railway sources said the wagons jumped off the rails at about 5 am at a place between Dhanbad and Gaya stations.
Important trains like New Delhi-Sealdah Rajdhani Express, New Delhi-Howrah Rajdhani Express, New Delhi-Bhubaneswar Rajdhani Express and Mumbai-Howrah Mail have been halted at different places.
Efforts are being made to divert Rajdhani Expresses through a different route, sources said.
Both the tracks in the route have been blocked. The tracks were damaged and efforts were on to restore the rail traffic, railway sources said.