A preliminary probe into the November 11 derailment of the Kolkata-Sairang Express near Digaru station in Assam has found that a key component of the train's main braking system was in an isolated condition in the locomotive, The Hindu reported. The six-member probe team found that the BP angle cock — the valve primarily responsible for applying brakes in the coaches — was isolated, which may explain why the brakes did not take effect when the crew applied them.

Source: The Hindu via Scoop

This follows our earlier report on the derailment itself, when the locomotive and five coaches of the Sairang-Kolkata service left the tracks at Digaru on the morning of November 11. Read the original derailment report

According to the probe account, the train crew — the loco pilot, assistant loco pilot and guard — said the braking system was working properly when they took charge of the train at Guwahati at around 5.30 am on November 11. Near Digaru, where the train was being received on a loop line to let the Guwahati-Jorhat Jan Shatabdi Express pass first, the brakes failed to slow it; the train overshot a red signal, hit a dead end and derailed at about 6.54 am. No deaths were reported, and Assam Chief Minister Himanta Biswa Sarma said four passengers sustained minor injuries.

The probe report does not identify who left the braking system in that state, or whether the crew overlooked the safety checks meant to catch it before departure. Advisories issued by some railway divisions after the accident have suggested, as a possibility, that staff may have closed the angle cock while attending to jammed brake pads at Panbari station and forgotten to reopen it — a suggestion the investigation has not confirmed.

Source: Indian White Paper

Board orders brake tests on every zone

Acting on the findings, the Railway Board has ordered all zones to enforce mandatory braking tests immediately, according to a report on the order. A safety drive runs from November 12 to 18 to ensure crews perform the checks, and zones must send their results to the Board by November 20.

Source: NEWire

Under the order, crews must perform a brake feel test by slowing the train from 15 kmph to 10 kmph. Passenger trains require a brake power test from 60-70 kmph down to 30-35 kmph, while goods trains must drop from 40-50 kmph to 20-25 kmph. An official quoted in the report said the Sairang crew "may have either failed to conduct the mandatory braking tests or relied on regenerative braking along with the main A-9 braking system while checking the train's braking capability."

The investigation into the derailment is continuing, and responsibility for the isolated valve has not been fixed. The Board's nationwide test order is the first system-wide corrective step to emerge from the Digaru accident.