Wifi blamed for Shenzhen Metro accident

2012-11-05 05:15:09 GMT2012-11-05 13:15:09(Beijing Time)  SINA English

By Yu Runze, Sina English

Mobile WiFi devices carried by passengers may have caused the disruption of Shekou Line Metro service last week, Southern Metropolis Daily reported Sunday, quoting sources close to the investigation.

Several Metro trains came to a sudden stop between 8:15 and 9 a.m. on the Shekou Line on Thursday, disrupted by signals. Many commuters were forced to change to other trains, and some were stranded at stations. Shenzhen Metro Co. said unknown signals activated the trains’ protection system, which halted the trains.

The company is analyzing the sources of the signals and an official announcement hadn’t been made as of late yesterday.

"Preliminary investigations showed some mobile WiFi routers carried by passengers to surf 3G networks sent signals on similar frequencies as Metro signal systems.

Tests showed the trains’ protection system would be automatically put into operation, resulting in emergency braking, when employees used the routers,” the newspaper said, quoting a Shenzhen Metro source. “The company is requiring mobile phone service providers to cooperate with the investigation.”

Hot spots appeared to cause the problem.

"The Metro company and mobile service providers suspected that signals sent by mobile phones operating as a WiFi hot spot, rather than ordinary signals sent by router devices, disrupted train services on the Shekou and Huanzhong lines in recent days,” the newspaper said.

The two Metro lines use an automatic braking system controlled by signals, known as a CBTC system.

Wang Mengshu with the Chinese Academy of Engineering was quoted by the newspaper as saying that CBTC was unlikely affected by 3G signals, but new signal devices, such as mobile hot spots, could cause new problems.

Editor: Yu Runze
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