A six‑member probe team examining the November 11 derailment of the Kolkata‑Sairang Express at Digaru railway station in Assam has identified a closed brake‑pipe angle cock as a possible cause. The BP angle cock, which regulates compressed‑air flow to the train’s brakes, was found isolated in the locomotive, meaning brake pressure could not be applied even though the crew engaged the brakes.
The preliminary note states that while the crew applied the brakes, the closed cock would have stopped them from functioning. The investigation has not yet determined who isolated the valve or whether the crew verified its position before the train left Guwahati.
According to statements from the loco pilot, assistant pilot and guard, the braking system was working when they took charge at Guwahati around 5:30 am. The train was later stopped at Panbari at 6:16 am after a coach’s wheels overheated due to jammed brake pads; after about thirty minutes the service resumed at 6:46 am. Approaching Digaru, the station master directed the train into a loop line, but the brakes failed, the train passed a red signal, struck a dead‑end track and derailed.
Safety experts suggest the crew may have relied on the train’s regenerative braking and only discovered the main brakes were inoperative when trying to stop at Digaru. They question whether the angle cock was left closed after the Panbari brake‑pad work and not reopened before the train proceeded.
