150 people were left waiting as engineers investigated the fault, and the other 28 cars were brought back into the nearest station.
But they couldn't get the faulty car fixed, and nine passengers had to be rescued by staff using ropes.
No-one was hurt, and Alton Towers say they had trained for such an event.
The park say stopping the ride was the normal thing to do if it broke down.
Liz Greenwood from Alton Towers told the BBC that the rescue effort went very smoothly.
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