Unconfirmed reports said that two people, including a train driver, were killed in the accident which took place near village Baghola in Palwal district, about 80 km from New Delhi.
An EMU (electric multiple unit) shuttle train collided with an express train which had halted on the same track.
The EMU hit the express train from behind. Dense fog was being attributed as the cause of the accident.
Rescue and relief work was promptly initiated by railways and district authorities and the injured were referred to hospitals in Palwal and Faridabad, officials said.
Haryana Chief Minister Manohar Lal Khattar spoke to Palwal deputy commissioner and asked him to step up rescue and relief work.