A 30-year-old woman and her five year-old son were seriously injured when they were thrown out of a train by miscreants who also robbed them off their valuables near Mughalsarai's Vyasnagar railway crossing, the police said today. The woman, identified as Mamata, was travelling from Asansol to Bareilly in Uttar Pradesh with her son Ajay on Kolkata-Lucknow Summer Special train late last night, they said. She was sitting near the gate of the general compartment when the miscreants tried to rob her. But when she protested they beat her up, robbed her of cash and other valuables and pushed her, along with her son, out of the train, the police said. The duo was lying beside the tracks when they were spotted by a passerby who rushed them to a nearby hospital in the Dulhipur area with the help of some locals, they said. Upon information, the police reached the hospital, from where they took the critically injured mother-son duo to BHU's Trauma Centre for treatment. A case has been registered against unidentified persons and an investigation is on, the police said.