Train movement under Samastipur rail division was hampered for around two hours on Friday morning when Darbhanga-New Delhi Sampark Kranti Superfast Express sped ahead leaving four coaches behind at Laheriasarai station in Darbhanga district.
Railway officials said the Delhi-bound train started its journey at 8.35am from Darbhanga station and reached Laheriasarai at 8.45am. Four coaches at the rear got unlinked when the train left the place, throwing the railway traffic out of gear.
"The railway officials called the next station Thalwara and 12565 Sampark Kranti was stopped there. The engine was sent back to retrieve the coaches left behind. We are investigating how the incident happened," said Samastipur railway division public relations officer AA Humayun.
The superfast express train could resume its Delhi journey after almost two hours when the coaches left behind were reattached.