Patna: Rail traffic disrupted due to the derailment of 12 bogies of the Delhi-Dibrugarh Rajdhani Express in Bihar's Saran district was restored partially on Thursday, an official said.

Railway official A.K. Razak said the lines on the Sonepur-Chapra rail section of the East Central Railway were cleared for traffic on Thursday morning.

"It will take another two or three hours to clear the down line for rail traffic," he said.

Also read: 4 killed, 8 injured as Delhi-Dibrugarh Rajdhani Express derails in Bihar

Traffic was completely disrupted after the derailment near Chapra, about 100 km from here, early Wednesday morning.

Over 40 express and passenger trains were cancelled, and another 22 trains were diverted, that left passengers stranded at different places.

At least four people were killed and 22 injured in the accident.

Railway Minister Sadananda Gowda, who visited the site on Wednesday, announced that Railway Safety Commissioner P.K. Vajpayee will conduct an inquiry into the derailment.