Shenzhen Metro shuts off 3G service for a day after trains inexplicably stop
Smartphone users in limbo as metro lines pull plug on data services to probe link between frequency's use and trains suddenly stopping
Passengers on two Shenzhen subway lines cried foul yesterday after authorities abruptly shut down 3G service to determine what has been causing trains to unexpectedly stop between stations.
Shenzhen Metro, which had been at a loss to explain the sudden train failures on the Huangzhong and Shekou lines, said it cut off the wireless signal for 24 hours in order to test a theory that interference from mobile wireless networks was to blame.
Almost every subway on the mainland uses the 2.4-gigahertz frequency for its wireless train operating system, the same frequency used by consumer electronic devices.
The outage infuriated passengers accustomed to fiddling with their wireless devices during lengthy commutes.
"Suddenly my iPhone returned to [the] Stone Age, with [the] capability only to make phone calls and send text messages," said Lai Mingjuan, who has an hour-long trip between her downtown office and home in the suburbs. "Without an internet connection I don't know what to do with my hands."
The 3G suspension added to public concern that Shenzhen Metro would seek to permanently end mobile data services on the trains. The Sina Weibo microblogging service was buzzing with passenger complaints and opposition to any long-term disruption.