A six-member probe team, in its report, found that the system primarily responsible for applying brakes in the coaches, technically known as the BP angle cock, was in an isolated condition in the locomotive. New Delhi, Nov 13 (PTI) A preliminary probe into the derailment of the Kolkata-Sairang Express at Digaru Railway Station in Assam on November 11 has pointed to a malfunctioning main braking system.