Published on January 19, 2005

Driver of empty train released airbrake instead of parking brake as instructed

Communication problems between a train driver and the control room were the main cause of Monday’s subway accident, a Transport Ministry fact-finding team has found.

A recording of the conversation between the control room and the driver of the off-duty train that crashed into a crowded passenger train showed that the driver accidentally released the emergency airbrake, instead of the parking brake as he had been instructed to by the control room, the team’s leader Samart Yonlapak said.

To disengage the airbrake, which is code-named B09, the driver deactivated the automatic braking system, explained Samart, deputy permanent secretary to the Transport Ministry.

In the recorded conversation, the train driver was heard shouting “I can’t stop it! I can’t stop it!” as his train started sliding backwards on the inclined rails leading to the maintenance depot, Samart said.

He added that the fact-finding team would need to conduct further investigations to determine whether Bangkok Metro Co Ltd (BMCL), which was awarded the concession to operate the underground system, provided adequate training for its drivers.

Prapat Chongsa-nguan, governor of the Mass Rapid Transit Authority of Thailand (MRTA), the state agency that oversees the subway system, said yesterday that it appeared the BMCL employees involved did not pay enough attention to what they were doing.

“The driver told the control room that he had released the B09 brake, and one official at the centre repeated what he had said without considering whether it was the correct thing to do,” Prapat said.

“They worked like parrots – just repeating what others said without thinking about whether it was the correct procedure.”

The MRTA chief noted that Siemens, the company that supplies the trains for Bangkok’s subway, advised against releasing the B09 brake, except in case of brake jams or other braking problems.

BMCL managing director Sombat Kitjaluck said yesterday that six company employees have been suspended from work following the accident.

The empty train had run into problems before the accident, grinding to a halt on a sloping curve leading to the maintenance depot. The driver applied the brakes and was waiting to be towed.

A rescue train was attempting to connect to the stalled train when the driver was told to release the brakes. It was then that the empty train began to slide backwards before colliding with another train, which was fully loaded with passengers.

Samart said yesterday that his fact-finding team had determined that instructions from the control room had been conveyed improperly and did not follow company guidelines.

He said that the probe team would today question the two drivers and the two officers in the control room who were involved in the accident. Conclusions could be drawn tomorrow, he added.

A source from the fact-finding team said yesterday that team members had discovered flaws in the subway system, including an ineffective communication system and the absence of a device in the depot to prevent a train from rolling back into the subway tunnel.

In related developments, a police investigation into the accident was underway yesterday, and more than 20 passengers and subway officials were questioned, said Maj General Kamol Kaewsuwan, the chief investigator.

He added that initial findings indicated the accident was not caused by a mechanical malfunction.

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