VALLEJO (CBS SF) — The Superman Ultimate Flight roller coaster at Six Flags Discovery Kingdom left passengers stuck, after reopening one week after it stalled mid-ride and stranded a dozen riders, a spokeswoman for the park said Sunday.

The roller coaster was cleared by safety inspectors and began regular operations earlier Sunday, Six Flags spokeswoman Nancy Chan said.

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Shortly after reopening, the ride suffered a glitch, leaving passengers stuck.  Park officials were able to quickly remove those passengers from the ride.

The park blamed the problem on a computer glitch.

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Cal-OSHA was continuing to investigate why the ride also stopped about 3 p.m. on July 29.

The Vallejo Fire Department responded to that incident, and two members were raised 150 feet on a mobile platform to reach the roller coaster. The coaster was un-jammed and rolled backward to its starting point.

No one was injured, though riders were stranded for about two hours.

Cal-OSHA had no deadline to finish its investigation into the incident.

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