Three live bombs were found on railway tracks near Biramdih station, 55 km from Purulia, which the Maoists burnt down early Wednesday as part of their two-day economic blockade.
Securitymen spotted the bombs on the up and down tracks within a kilometre from Biramdih station, South Eastern Railway sources said.
The signalling system of the station was destroyed by the fire, affecting train movement in Purulia-Chandil section of Adra division.
Bomb disposal squad personnel had left from Kolkata to diffuse the bombs which were probably planted targetting Chennai-Guwahati Express and Delhi-Bhubaneswar Sampark Kranti superfast train, sources said.
The trains were diverted through Kotshila and Tatanagar while a few local trains were cancelled.
Assistant Station Manager of Biramdih, Dhaneswar Mundara, who was on duty last night, said over 40 armed maoists raided the station at about 1.30 am and asked three railway employees and three unarmed RPF personnel to leave at gunpoint.
Then they poured petrol and burnt the station, destroying signalling apparatus, furniture and many documents of the station, situated about 55 km from Purulia in Purulia district bordering Jharkhand.
The two-day economic blockade entered its final day on Wednesday with the CPI (Maoists) protesting against the state and Centre's globalisation, industrialisation and SEZ policies.
Armed police led by district Superintendent of Police Ashok Kumar Prasad and officials of Adra division reached Biramdih. Both West Bengal Police and Jharkhand Police have launched a hunt for the Maoists.