OAKLAND (KCBS) – BART was shut down for 20 minutes Wednesday morning when a system controller inadvertently triggered a disaster training scenario.

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Agency spokesperson Taylor Huckaby told KCBS that a technician at the underground Operations Control Center in Oakland typed in a code that shut the system down around 10 a.m.

Huckaby said changes will be made.

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“We are taking steps to ensure that emergency command can only be approved with two managers, or two people in the Operations Control Center so that it just can’t have one point where the entire system is shut down,” Huckaby said.

During the glitch, most of the trains stopped or returned to the nearest station.

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Huckaby said they quickly reset the system but residual delays lasted an hour.