More than 40 people had to be rescued after they were trapped for 55 minutes on a ride at Surrey's Thorpe Park.
The Slammer ride opened in 2005 and rotates 360 degrees
The Slammer - a "rotary thrill ride" - ground to a halt on Saturday afternoon after developing a technical problem.
The ride operators said an emergency "fail-safe" system immediately kicked in and the ride was righted.
Safety checks are being carried out and the ride will remain closed until the cause of the malfunction is detected, a spokeswoman said.
She said the ride had been checked before the park opened on Saturday morning.
"Like all the rides and attractions at the park this ride undergoes a comprehensive series of pre-opening checks every morning by our experienced engineering team," she said.
Emergency services were called but park staff were able to free the riders.