The armed Maoists, numbering about 20, took the railway employees hostage when they were repairing railway tracks 3 km from Ghorparan station located between Jasidih and Simultala stations on Jhajha-Jasidih section, Simultala station master R N P Yadav said.
The ultras took all the railway employees to a nearby forest where they released 16 of them, including section engineer Soren Manjhi and Permanent Way Inspector Bhuwaneshwar Manda, he said.
Three other railway employees, Ghorparan station master Vijay Kumar and porters Munna Kumar and Dukhan Mahto, were released later by the Maoists, an Eastern Railway release said in Kolkata.
Railway Minister Mukul Roy told PTI in Kolkata, "We have spoken to the Bihar Home Secretary and the Inspector General of RPF has talked to the Bihar DGP."
The Chairman of the Railway Board was also in touch with the Bihar government and the Union Home Ministry, he said.
Jamui District Magistrate Mayank Barbare, Superintendent of Police Upendra Kumar Sharma and Sub-Divisional Officer Amlendu Kumar camped at the spot to supervise rescue operations launched by the CRPF's CoBRA battalion and the district police.
Train services, disrupted on the Howrah-Delhi main line after the incident at 10:30 hrs, resumed at 14:02 hrs, the railway minister said.