Guwahati: The Railway Board has instructed all railway zones to ensure that running crews conduct mandatory braking tests after taking charge of trains, following the derailment of the Kolkata-Sairang Express near Guwahati on November 11.

In a directive issued on November 11, the Board also ordered zonal railways to undertake a special safety inspection drive from November 12 to 18 to verify whether locomotive crews are conducting the prescribed brake feel and brake power tests. Any lapses identified during the exercise must be documented and reported to the Railway Board by November 20.

A preliminary inquiry into the derailment at Assam’s Digaru railway station has indicated a possible malfunction in the train’s main braking system. The six-member inquiry team found that the BP angle cock, a component associated with the braking system in passenger coaches, was in an isolated position in the locomotive.

However, the preliminary findings have not established who isolated the braking system or whether the running crew failed to follow the mandatory safety procedures before operating the train.

Railway officials said the latest directive reiterates existing safety protocols, compliance with which is suspected to have been overlooked in the Kolkata-Sairang Express incident.

Railway Board reinforces braking test procedures

Under the prescribed brake feel test, the locomotive pilot initially brings the train to approximately 15 kmph before applying the brakes through the main braking system, known as A-9. The speed should then drop to around 10 kmph, enabling the crew to assess whether the braking system is functioning properly.

During the brake power test, passenger trains are accelerated to 60–70 kmph before the brakes are applied to bring the speed down to 30–35 kmph.

For goods trains, the corresponding speed limits are 40–50 kmph before braking and 20–25 kmph after the test.

The Railway Board has also stressed the responsibility of the assistant loco pilot (ALP) in ensuring that both tests are performed. The assistant loco pilot must remind the locomotive pilot if necessary and independently monitor the effectiveness of the braking system during the tests.

Possible communication gap during Guwahati locomotive change

According to railway sources, a possible communication failure during the locomotive handover at Guwahati may have resulted in the BP angle cock being left in an isolated position.

The Kolkata-Sairang Express previously underwent a routine locomotive change at Guwahati, where its electric locomotive was replaced with a diesel engine. During this procedure, railway staff would isolate the BP angle cock.

However, following the completion of electrification along the route, the locomotive change was discontinued in recent days. The electric locomotive subsequently began operating the train beyond Guwahati.

A railway official said the employee responsible for isolating the angle cock was on leave when the earlier locomotive interchange arrangement was discontinued.

When the employee returned to duty on November 11, he reportedly followed the previous procedure and isolated the angle cock, apparently unaware that the electric locomotive would continue operating the train beyond Guwahati.

The official also suggested that the train crew may have either skipped the mandatory braking tests or relied on regenerative braking alongside the main A-9 braking system while assessing the train’s braking capability.

The crew may have realised that the main braking system was not functioning properly when they attempted to stop the train near the loop line, potentially contributing to the derailment, the official added.

The possible communication gap, procedural lapses and circumstances leading to the accident are currently under examination.