Faulty tracks caused North East Express derailment: Prelim report

What derailed the North East Express? Was it a technical failure or a man-made disaster? According to a preliminary report, the Express train derailed due to a faulty track at Raghunathpur in Bihar when cruising at 128 kmph.
Signed by 6 railway department officials, the report quoting the loco pilot, said that a massive jolt was experienced at the rear end which caused the train to vibrate. Ultimately, the train could not sustain excessive vibration and the brake pipe pressure dropped suddenly leading to the derailment of 21 bogies, the report said.
The report said that the gateman and points man of the Raghunathpur railway station had noticed sudden sparks emanating from the wheels of the train before the mishap. It is learnt that the Railway authorities also conducted a breath analyser test on both the loco pilots. It was found that both of them were not under the influence of alcohol.
“The derailment occurred due to fault in tracks. The cost of damage to railway property due to the accident is estimated at Rs 52 crore. The loco pilot, Vipin Kumar Sinha, and his assistant also sustained injuries in the accident,” the report signed by the railway officials including the loco pilot mentioned.
At least four passengers died and another 50 were injured after 21 coaches of the North East Express train derailed near Raghunathpur station in Buxar district.
Among those deceased were Usha Bhandari-33 yrs and her 8 year old daughter Aakriti from Assam and Abu Zaid, 27, and Narendra, 32 years old.