Alton Towers operator Merlin Entertainments attended Stafford Crown Court today (26 September) for the sentencing hearing for the June 2015 accident. Prosecutor Bernard Thorogood told the court the kinetic energy involved in the crash was equivalent to a "family car of 1.5 tonnes having collided at about 90 mph".
Two people had their legs amputated and three others suffered life-changing injuries after two carriages collided on the 14-loop ride.
Merlin admitted breaching s 3(1) of the Health and Safety at Work Act earlier this year and could be fined up to £10m under new sentencing guidelines for safety and health offences.
The court heard that an empty test carriage had been sent round the rollercoaster. It failed to clear one of the loops and stopped in a valley of track, unseen by staff. The Health and Safety Executive (HSE) found strong winds could have been the reason the empty carriage failed to complete the loop.
The rollercoaster's computer system halted the ride but engineers manually overrode it. They "distrusted" the ride's fault signal, believing it to be an error, and sent a full car along the track and into the path of the empty carriage.
The regulator concluded that the Smiler ride had been well designed with a complex control system and the operator followed safe working practices.
Merlin, however, was said to have fallen "far short" of controlling the need for engineers to fix faults and there was "no evidence of a task analysis-based approach for engineering work, in particular in dealing with ride faults".
In mitigation for Alton Towers, barrister Simon Antrobus said: "[The company] accepts its responsibility that this should never have happened and accepted that the accident was attributable to failures that, while they were never intended, would have been avoidable with greater care."
"It's a good organisation that made a serious failure, but is one that is of otherwise good character."
Since the crash, Alton Towers has made 30 changes to improve the safety of the Smiler ride.