Authorities in India's West Bengal state say at least 50 people were killed and some 100 were injured when one train crashed into another early Monday in eastern India.

The authorities say the crash happened at about 2 a.m. local time when an express train slammed into a stationary train at Sainthia station in Birbhum district, about 200 kilometers north of Kolkata, the state capital.

Television footage showed mangled wreckage of several carriages.  The force of the crash was so strong that the roof of one car flew into the air and landed on an overpass above the tracks.

Rescue workers were looking for passengers who could be still trapped inside the wreckage.

India's heavily-used rail network is one of the world's largest, with some 9,000 passenger trains carrying 18 million people every day.  There are about 300 Indian rail accidents every year.

Some information for this report provided by AP, AFP and Reuters.