The train was on its way to Gauhati in Assam state from Bikaner, a city in Rajasthan, when the crash occurred in Jalpaiguri on Thursday.

A total of three coaches overturned.

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Rescue teams found four bodies last night as they searched through the mangled metal and debris.

Images from the scene showed passengers stuck inside the destroyed coaches as rescuers tried to pull them out.

Railway authorities have ordered an investigation into the cause of the accident.

Meanwhile, the 45 injured are being treated in hospital, senior police officer Debarshi Dutta said.

Families of both the deceased and injured will receive financial compensation from the Indian government.

Accidents are particularly common on India's vast ageing rail network.

Safety standards remain a concern over the state-run system, which operates 9,000 passenger trains and carries about 23 million commuters every day.

In 2016, 127 people were killed when 14 coaches derailed in Uttar Pradesh state in one of India's worst train accidents.