HOW DID 'HUMAN ERROR' CAUSE HORROR ROLLERCOASTER CRASH?
The
most fundamental safeguard on the German-built £18million Smiler ride
at Alton Towers is that two carriages should never be able to travel on
the same section of track at the same time.
Special
sensors trigger a braking device to prevent this happening but this
safety mechanism was 'overrode' manually on the day of the crash.
It
is understood the ride was suffering 'technical difficulties' on the
day of the crash, June 2, and an empty 'test' carriage was sent round
the ride to check it was in working order.
At the same time, 16 passengers were loaded into a separate carriage and the ride got underway.
But
the full carriage was soon halted at the top of the first upward
section of the rollercoaster as the automatic brakes kicked in.
It
meant the computerised safety system was working perfectly as the
sensors were being told there was another carriage - the empty 'test'
carriage' - on the same section of track, even if operating staff were
inexplicably unaware of it.
It
is understood an engineer engaged a 'manual override' of the safety
system at this point, allowing the carriage with passengers on board to
continue once the ride operator had restarted the system.
However, as the ride restarted, the empty 'test' carriage remained on the track following the earlier tests.
It
meant the carriage full of passengers plummeted at around 50mph into
the stationary carriage on the track, leaving the victims stranded in
mid-air for up to four-and-a-half hours while rescuers desperately tried
to reach them.
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