A preliminary probe into the derailment of the Kolkata-Sairang Express at Digaru Railway Station in Assam on November 11 has identified a malfunctioning main braking system as the likely cause of the accident. A six-member investigation team reported that the BP angle cock, the component primarily responsible for applying brakes in the coaches, was found in an isolated condition within the locomotive. The joint note prepared by the team on the day of the incident stated that this isolation likely prevented the brakes from engaging when required.
The report indicates that while the train crew applied the brakes, they may not have functioned because the angle cock was previously in a closed position. The investigation did not determine who disabled the system or if safety checks were overlooked. However, statements from the loco pilot, assistant loco pilot, and guard asserted that the braking system was functioning correctly when they took charge of the train at Guwahati around 5:30 am on November 11.
According to the findings, the train stopped at Panbari station at 6:16 am after overheated wheels were detected due to jammed brake pads. After the crew addressed the issue and the train remained halted for approximately 30 minutes, it departed at 6:46 am. As the train approached Digaru station, the station master signaled it to enter the loop line to allow another train to pass. The brakes failed to work when the crew attempted to stop, causing the train to overshoot the red signal, strike a dead end, and derail.
