A herd of elephants was crossing the railway track in Champua forest range area when they were hit by a wagon carrying coal from Paradip to Jamshedpur, a senior forest official said.
While a tusker and a female pachyderm died on the spot, an elephant calf was injured after being flung into a ditch near the railway track, Champua forest ranger S Mishra said.
The driver of the goods train, Gautam Patel, has been arrested and the train detained at Jurudi railway station, he said.
Keonjhar DFO Ajay Kumar Jena and other senior forest officials rushed to the site after the mishap.
Train movement on the route was disrupted for a long time as the carcasses were lying on the track.
Two other elephants were killed after a train hit them recently in the same area, the sources said.