NZM-Kota Jan Shatabdi: एवरेज स्पीड में नंबर वन, जिसमें नहीं है सवारियों का टोटा, यह है आपणी जनशताब्दी From कोटा - Madan Mohan Meena

If the train was going at moderate speeds, ( may be 40-70 kmph,) it would not have been very dangerous. Our trains now use air brakes. Because of this, whenever there is a train parting, brakes are automatically applied due to loss of brake pressure, and the LP can notice it too without actually looking back at the train. Unless the train was going at a high speed on a curve or if the parting is accompanied by a jolt, rake parting, in most cases will not result in a derailment. Any train that may be following the parted rake poses more danger than the rake parting itself. Thank god, there was no such thing in this case.
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It would be premature to call this negligence or an accident. Improper engaging of couplers is a well known problem with CBC couplings, ( like the infamous jerks in CBC coaches, which also can be reduced, but never fully eradicated). This does happen occasionally even with well maintained and monitored equipment. And that too in this case, an emergency brake was applied. This along with the jerk while starting, could have dislodged the locking mechanism. Unless proven otherwise, I am inclined to think that this was just an unfortunate incident.