Fault in braking system was the main reason for Kolkata-Sairang Express derailment

A preliminary investigation has revealed that a fault in the train's main braking system was the reason behind the derailment of the Kolkata-Sairang Express near Digaru railway station in Assam on 11 November, according to a report by The Hindu.

A six-member special team was formed to investigate the accident. The report prepared by this team stated that the system primarily responsible for applying brakes to the coaches, technically known as the 'BP angle cock', was in an isolated position in the locomotive. The joint notes prepared by the investigation team on the day of the accident stated that when the FP/BP angle cock of the locomotive was in an isolated position, brakes could not have been applied, and this could be the reason responsible for the accident.

The report further added that the train's crew members had attempted to apply the brakes, but the brakes could not be applied as the angle cock was already in the off position. However, the investigation report has not provided any specific identification regarding who damaged this braking system or whether the crew members made any error in the safety procedure to check its efficiency before operating the train.

Meanwhile, the train's crew members—including the loco pilot, assistant loco pilot, and guard—stated in their statements that the braking system was working properly when they took charge of the train from Guwahati at 5.30 am on 11 November.

According to the report, the train was stopped at Panbari (PNB) station at 6.16 am because it was found that a coach's wheels had become excessively hot due to jammed brake pads. The crew members had attempted to resolve this issue, due to which the train remained stationary at this station for about 30 minutes.

When the train departed from Panbari at 6.46 am and was moving towards Digaru station, the station master signaled it to enter the loop line and stop there to allow another train to pass. According to the report, when the crew members applied the brakes to stop the train, it failed. Consequently, the train crossed a red signal and eventually hit a dead end and derailed.

Some security experts believe that the crew members might have been using the alternative braking system available in the train, known as the regenerative braking system, to control speed during the journey. They might have used the main braking system while attempting to stop the train near the loop line, only to find it non-functional.

Raising questions regarding the incident, a security expert stated, "Who isolated the main braking system? Did the railway staff do it and then forget to reactivate it?" Looking at the sequence of events, the possibility of any outsider's involvement seems negligible, but the incident raises several questions that require a deep investigation.

An advisory issued by some railway departments following the accident suggests the possibility that while fixing the jammed brake pads at Panbari station, the railway staff might have closed the angle cock and forgotten to open it before restarting the train.

The Kolkata-Sairang Express was a passenger train operated by Indian Railways running between Kolkata and Sairang.