A passenger was injured when two unidentified gunmen fired at him in an air-conditioned coach of Danapur-Howrah Superfast Express near Mokamah Railway Station in the district, a senior officer said on Sunday.
Two youths boarded the AC-111 coach of the train at Barh railway station and picked up a quarrel on Friday night with the passenger identified as P K Mukherjee, SRP (Patna) J S Rana said.
The youths were trying to occupy Mukherjee's berth which led to the altercation, he said.
After a heated argument, they fired at Mukherjee when the train was approaching Mokamah and fled away after pulling the chain, Rana said.
Mukherjee was given first aid at a hospital in Mokamah after which he was sent to Howrah on Saturday.
An FIR was lodged by railway police at Mokamah and raids were on in the area to track down the attackers, Rana said.