The Smiler Incident 02/06/15

[Ryan.B]

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.

[Guitar]

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.

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.

[Guitar]

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.

The operators of the ride have to undergo much more rigorous training than shop assistants. The shop assistants probably assumed that the operators knew what they are doing. Reading threads on here makes it clear that the GP tend to not know what they are talking about. So its understandable that the GP were ignored for the most part (not neccessarily right, but understandable). And the rider helpers and operators probably assumed that engineering team (the only people with keys for resetting the ride) knew what they were doing.

Also how did they phrase it? A member of this forum would probably phrase it as "There is a train valleyed in the batwing". A member of the public might just say "there is a train stuck on the track". Well the ride was in a reset, all 4 trains were "stuck".

[Dan]

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.

"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]

"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"

Thanks for posting the quote.

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.

But in terms of the accident the amount of energy involved is somewhat unimportant. The damage done to the riders doesn't depend on the energy involved, it depends on the rate at which it is dissipated, and where it is dissipated.

[mark_h]

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.

No-

E_k = 1/2 m v²

so if the kinetic energy was equal and v_c = speed of car, v_s = speed of smiler, m_c = mass of car, m_s= mass of smiler

then

m_c v_c² = m_s v_s²

so m_s = m_c (v_c/v_s)²

so if the car weighed 1.5 tonnes and the was traveling at 90 mph and the smiler car was traveling at 20 mph then the smiler car would weigh 30.375 tonnes.

[Guitar]

Clearly the trains on smiler do not weigh 30 tons.

[Dan]

Clearly the trains on smiler do not weigh 30 tons.

I believe the train was travelling at around 40mph on impact.

[Alex]

In the trading update from this morning they've reported that visitor numbers have started to increase again although they're still significantly below 2014 levels.

[Tryst]

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-towe ... ler-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.

[Kraken]

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-towe ... ler-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.

Interesting article, but your take on it seems to suggest that Technical Services staff were to blame for the accident.

The Head of Technical Services is still the same guy who has been in the job for many years - if one of his staff had caused the accident, the buck would have stopped at his office door & you would, not unreasonably, expect him to be seeking employment elsewhere.

By contrast, the Head of Park Operations [a very competent person too] quietly resigned early last year, ahead of the HSE report on the incident.

Draw your own conclusions. I think even Nick Varney knew exactly what had happened on the day it all did, but he could obviously say nothing whilst the HSE were investigating.

[Lee]

I would be very careful with those rumoured accusations Kraken as there is very little substance to them. What you are saying is circumstantial at best.

The report that Tryst has condensed was very much the conclusion of the court and widely circulated by the papers. The same independent report also praised the Park Operations team on their processes and paperwork and was emphasised in court.

[ThemeCrafter264]

I read an interesting article about Merlin and their new safety since the accident. The link is https://blooloop.com/feature/safety-smi ... tainments/

[Smiley]

so if the car weighed 1.5 tonnes and the was traveling at 90 mph and the smiler car was traveling at 20 mph then the smiler car would weigh 30.375 tonnes.

Incorrect. What Dan quoted was "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"

A modern family car has airbags. It has crumple zones at the front and structures on both front and rear (of the car in front) that can absorb energy from an impact. It has self-tensioning seat belts including the important "lap belt" across the pelvis. It has different (padded) seating that can absorb energy and limit injury, and a different configuration of leg room.

So whilst the kinetic energy might have been the same, it does not mean that the injuries are the same. Hence why a F1 car can crash at 200mph and the driver walk away, but the driver of a Caterham 7 not

[mark_h]

Incorrect. What Dan quoted was "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"

My post was correct

It seems that the prosecutor Bernard Thorogood lacks a basic knowledge of the equations of motion using scientific terminology that he does not fully understand.

My post was exploring the physics of his statement and correct Guitar’s post which had errors.

Thorogood stated that “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”

Kinetic energy is a specific term that refers to the energy of the moving body which is purely a function of velocity and mass (1/2 m v²).

Equivalent is defined by the OED as “Of weights, measures, numerical expressions: Equal in quantitative ‘value’.

Had he described the effect of the crash on the occupants as equivalent to that of “a family car of 1.5 tons having collided at about 90mph” then the statement would be more correct.

[PJ.]

I wonder if this terrible event will have any bearing on the Smiler? (Although on the surface it looks like it was down to the gent having no legs so no safe on a coaster with just a lap bar http://www.ladbible.com/now/weird-disab ... r-20170414" onclick="window.open(this.href);return false;


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[Tryst]

I wonder if this terrible event will have any bearing on the Smiler? (Although on the surface it looks like it was down to the gent having no legs so no safe on a coaster with just a lap bar http://www.ladbible.com/now/weird-disab ... r-20170414" onclick="window.open(this.href);return false;

"The last major incident involving a roller coaster here in the UK was at Alton Towers, when the Smiler ride crashed."

So Tsunami at M&D's coming off the rails and landing on top of children's attraction was a minor event, barely worth reporting on?

[RockandGrohl]

I'm wondering why the Smiler test car stalled in the first place? Anyone have any ideas? Thank you.

[Nickolai]

It seemed to be due to the very high winds. The ride operated in higher winds than what Gerstlauer advised.You can see in the CCTV that it stalls for ages at the top of the inversion before valleying, showing the huge possibility that it could have cleared the inversion. Unfortunately however that didn't happen...

[Capt.Barnacles]

This is literally the only thing that surprised me. The fact that the empty vehicle actually stayed at the top of Inv. 6 for a good 20 seconds. Along with everything else that day, some pretty astronomical odds for that to happen!