Dan wrote:Guitar wrote:90 mp/h? Smiler has a top speed of ~85 km/h, or ~52mp/h. according to wikipedia the Smiler crash occured at ~20 mp/h.
There's no way this was a 90mp/h crash, just watch the video.
It wasn't said that the crash occurred at 90mph.
It was said however that the forces involved in the crash were equivalent to a 1.5 tonne family car crashing at 90mph.
I don't have the scientific knowledge to say how accurate this is but given it was put to the judge in court I'd say it was likely.
Ryan.B wrote:Always thought before the crash that there was a staff member or two on the smiler entrance, and you could see the batwing from the shop. I know members of the GP told staff the ride had stopped, but how not one single staff member didn't notice and inform the engineers is beyond me.
Do you have a link to the quote(s) where that was stated? I don't doubt that it was said but I'd like to see the context.
The 90mph car crash makes it sound worse than it is. Roller coaster trains are much heavier than a family car, so yes there is a lot of force involved, but it hit a similarly large object, so the force has a much larger area to dissipate against compared to a family car. You could also go the other way and say its the equivalent of an ocean going liner crashing at 0.05 mp/h. Which doesn't sound bad at all (in terms of the speed).
If I can find the quotes and the context I will happily do the actual maths.
But it's the dissipation of energy that's important, the energy wasn't and shouldn't be dissipated through the occupants of the ride. Ok some will be, but the bulk of the energy will be dissipated through the chassis of both trains.
The 90mp/h figure is probably correct in terms of the forces involved, but it's a bit disingenuous as it's not the important factor to judge the damage done to the riders.
Dan wrote:"Prosecuting, Bernard Thorogood told the court that the passengers on the £18 million ride watched with “disbelief and horror” as they realised they were going to collide with an empty carriage.
He said the kinetic energy involved in the crash on June 2 2015 was equivalent to “a family car of 1.5 tons having collided at about 90mph"
Guitar wrote:So if the crash happened at 20mp/h then that must mean the trains on smiler are around 6.75 tons.
To turn 90mp/h into 20mp/h you divide 90 by 4.5 so you then have to multiply the 1.5 tons by the same value (4.5) equalling 6.75 tons.
Guitar wrote:Clearly the trains on smiler do not weigh 30 tons.
Tryst wrote:When the HSE announced the fine against Alton Towers last year, I didn't notice that there was a report in the Zip file attached to the press release http://press.hse.gov.uk/2016/alton-towers-owners-fined-over-smiler-crash/. It is an expert witness report by Steven Flanagan, an independent consultant and former head inspector of fairgrounds and amusement parks from 1991 to 2013. Flanagan made the following conclusions in relation to the Smiler incident, which I will reproduce here to save you downloading a very large Zip file:
1) "The Smiler was designed to current standards, has a sophisticated control system and an ergonomically sound user-interface for operators." (Ergonomics being used in a technical context to describe the engineering discipline of human-machine interaction, rather than merely 'comfortable'. --T)
2) "The arrangements (system of work, training and supervision) put in place for ride operation by the Operations department were based on sound safety engineering principles, and provided an adequate basis for safe operation in 'normal' mode."
3) "The Technical Services department either failed to recognise the safety critical nature of the task of dealing with faults to the ride, or else lacked the safety engineering expertise to devise systems which would deal with the inherent unreliability of relying on human actions in a safety critical situation."
4) "The consequence of the Technical Services department's failings was that a situation arose where serious error was a potential outcome, and that outcome materialised."
Flanagan goes on to say that the new arrangements put in place by Merlin as a result of the incident are adequate to prevent this type of incident reoccurring. He also has a significant poke at the senior management of Alton Towers Operations for not acting on the "manifest inadequacy" of the safety arrangements in the Technical Services department.
The report goes over the accident in some detail. One of the significant contributing issues was that the two engineers sent to check that the block was clear were not made aware of the fact that there were 5 cars on the track and not 4. When they saw that the brake run at the bottom of the second lift was clear, they assumed that all 4 cars had been accounted for and pushed the button at the side of the track that allowed the two other engineers in the control room to clear the occupied status of the block. As they were unaware that there was a fifth car, they did not look for it, hence overlooking the stalled car entirely.
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