The robbers shot and injured school teacher Vishwakarma Sharma before looting the other passengers between Karauta and Bakhtiyarpur stations near Patna.
Sharma was admitted to a hospital here, where the doctors described his condition as stable.
Five policemen who failed to act during the incident have been suspended, authorities said here Monday.
The police have registered a complaint against eight people. Though no arrest has been made yet, three people have been detained for interrogation. 'The railway police along with local police are conducting raids to nab the criminals,' police said.