The down Agartala-Sealdah Kanchanjunga Express derailed between the New Haflong and Jatinga Lumpur station in Assam on Thursday, but no one was injured in the incident, Northeast Frontier Railway sources said.
One bogey adjacent to the engine derailed as a pair of its wheels slipped from the track when a buffalo came in its way at around 1.50 pm, the sources said.
The buffalo was killed after being run over, they said.
Following the incident, train services in the hill section between Lumding and Silchar were affected, the sources said, adding, restoration work on the track is underway.