A 32-year-old man has been airlifted to hospital after after an accident at a theme park in North Yorkshire.
The ride is described as a "favourite" among visitors
The man, who is a member of staff, was working as an operator on the Magnum Force roller coaster at Flamingo Land park near Malton.
He was badly injured after stepping into the path of the ride at 1200 BST on Tuesday.
He was taken to The James Cook Hospital on Teesside. The Health and Safety Executive has begun an investigation.
Flamingo Land chief executive Gordon Gibb said the park was co-operating fully to complete investigations.
He said: "As yet it is not known why the operator was in a part of the ride where only experienced mechanics are authorised to be."
A season ticket holder from Leeds, said she was told by a worker at the theme park how the injured man was struck by a train.
She said: "We were standing just a few yards away in the queue.
"We asked a litter collector what was happening. He said a worker had jumped over a safety barrier on his way to the toilet when he was hit by the car.
"He said he was hit full on. It was horrific. People were just shocked. They couldn't believe what had happened."
A spokeswoman for the Health and Safety Executive confirmed two inspectors were already on site conducting an investigation.
A spokesman for the Great North Air Ambulance service said the man had been treated at the scene by the on-board doctor before being air-lifted to hospital.
The ride is Europe's only triple looping roller coaster and is described on the theme park's website as a "monster of a ride".
It opened in 2000 and has a 3,444ft-long track with three loops, and can reach a top speed of 53mph.
The web site entry adds: "This true favourite thrusts the unwitting passenger along a mile of twisting track at breakneck speed while offering a spectacular view of the Yorkshire Moors from a breath taking height of 100ft."