The accident occurred as the goods train was moving out of Sikir and the express train was entering the station on the same track, Bolangir Superintendent of Police Ajay Kumar Sarangi said.
The trains collided head on causing injuries to at least 26 persons, he said.
The injured were admitted to hospital at Titlagarh where the condition of some passengers was stated to be serious, Sarangi said, adding a relief train was rushed to the accident site from Titlagarh.
The 18108 Koraput-Rourkela Express had stopped Titlagarh station a few minutes before the accident and it did not have a scheduled stop at Sikir.
Senior railway officials rushed to the site and efforts were on to ascertain the cause of the collision, which occurred shortly after 12.30 am, railway sources said.
Train services were affected on the track following the accident and efforts were on to restore normal traffic, they said.