A three-foot portion of the railway track was found missing, the police had said earlier.
"The track was tested on February 27 using ultrasonic flaw detectors (USFD) and no defect was found. So, the possibility of involvement of extraneous factors in causing damage to the track cannot be ruled out," said a source in the railway ministry.
The next USFD test of the track is due on April 27 as the automatic test of railway tracks is done every two months.
Besides, the source said, five trains had passed over the track prior to the ill-fated Rajya Rani Express and the loco pilots of those trains had not reported any unusual occurrence.
The real cause of the derailment will be known only after the completion of the inquiry, but there were indications towards sabotage, the source added.
Eight coaches of the Rajya Rani Express derailed near Rampur in the morning. The mishap occurred two kilometres from Rampur Junction railway station and about 100 metres from the Kosi river bridge, resulting in injuries to passengers and rail traffic disruption.
The railways has ordered an inquiry into the incident and announced an ex-gratia of Rs 50,000 each for the injured passengers.
Disclaimer: No Business Standard Journalist was involved in creation of this content
