At least 40 people have been killed when a passenger train rammed into a goods train near a railway station in the central Indian state of Uttar Pradesh.

The mishap was caused by a signal failure that left a passenger train speeding into a stationary freight train at Sant Kabir Nagar, about 225 km from state capital Lucknow, local media reported.

Gorakhpur-bound Gorakhdham Express was running at high speed when its drivers realised they were hurtling down a track on which a freight train was standing.

The driver slammed the brakes but the express crashed into the goods train. The driver and the assistant driver of the express train were in critical condition.

The station master apparently disappeared after the accident and the authorities are searching for him, the Associated Press reported.

Three general coaches of the Gorakhdham Express were mangled in the crash, while six other coaches derailed.

While the district administration confirmed 40 people died in the collision and more than 100 injured, the railway authorities have withheld the number of the dead and injured.

"People are saying this based on their own assessment. There are lot of people inside the coaches who need to be rescued first," a railway official said, according to the Times of India.

The railways have not confirmed that signal failure caused the accident. After preliminary investigations, the authorities said the accident was caused by the derailing of some of the coaches of the passenger express.

Prime Minister-designate Narendra Modi offered condolences to the families of those killed. He also tweeted that he has asked for a high-level investigation into the accident.

More than 20 million people travel by train in India every day.