Alton Towers' newest rollercoaster, Smiler, will remain closed while the theme park's technical team investigate reports that a bolt fell from the ride.
Just under 50 people were on the ride at the time and had to be rescued.
A spokeswoman for Alton Towers said:
On Sunday 21st July, in line with our standard procedures, Alton Towers Resort closed The Smiler to investigate a small piece of debris that had allegedly fallen from the track.
At no time was any visitor at any risk, and 48 guests on the ride at the time were safely disembarked.
As the health and safety of our guests is our primary concern, the ride will remain closed whilst the resort's technical team investigate.