Alton Towers, owned by Merlin Entertainments, has been fined £5 million for the Smiler rollercoaster crash which injured 16 people in last summer.
Judge Michael Chambers QC described the incident as a “needless and avoidable accident in which those who were injured were lucky not to be killed”.
The crash was exacerbated by the design which left the victims hanging for four to five hours waiting for emergency services to rescue them.
Two young women on the Smiler ride suffered leg amputations and others suffered severe injuries when their carriage collided with a stationary carriage on the same track on June 2, 2015.
The judge said at Stafford Crown Court: “It has rightly been the focus of much public interest, they operate on a high duty if public care. Merlin fell far short of standards.”
The court heard that on the day of the incident engineers overrode the Smiler’s control system without the knowledge and understanding to ensure it was safe to do so.
Merlin admitted charges of breaching the Health and Safety Act in April.
Neil Craig, head of operations for HSE in the Midlands said: “This avoidable incident happened because Merlin failed to put in place systems to allow engineers to work safely on the ride while it was running.
“Since the incident Alton Towers have made improvements to the ride and their safety protocols, and the lessons learned have been shared industry wide.”