Guest taken to hospital after metal object falls off TTD
James Parker jr
Yep. Xcelerator never closed, is older, operates at a year round park and is operated by Cedar Fair. This wasn't design related IMO. I believe they know it was some level of maintenance failure, and knew pretty quickly.
CP Coaster Top 10: 1. Steel Vengeance (40 rides to date) 2. Top Thrill Dragster (191 launches to date, 4 rollbacks) 3. Magnum XL 200 4. Millennium Force 5. Maverick 6. Raptor 7. GateKeeper 8. Valravn 9. Rougarou 10. Gemini
CedarPoint150
I’m not proud of the 3rd shift maintenance team for not ensuring this part was screwed on correctly. Some of the trains were making a weird “clanking” sound coming in through the brake run weeks prior to the incident. I point the finger at them. Their main job is to inspect each and every part of every train every night before signing off that it’s good to run in the morning.
djDaemon
That's an awful allegation to make in the absence of evidence.
Brandon
JoshBrown
CedarPoint150 said:
I’m not proud of the 3rd shift maintenance team for not ensuring this part was screwed on correctly. Some of the trains were making a weird “clanking” sound coming in through the brake run weeks prior to the incident. I point the finger at them. Their main job is to inspect each and every part of every train every night before signing off that it’s good to run in the morning.
2 posts to your name and you are slandering the third shift maintenance team? Yes they are supposed to preform regular inspections, but im not sure how you expect them to catch a (from my assumption) metal fatiqued bolt, especially on a non structure critcal part. Also if there was "clanking" as you say, can you with 100% certainty confirm it was specifically coming from the green train? If so why didnt you feel compelled to report it to park operations? Or the ride host? Surely if it was making an abnormal noise for "weeks" as you say, im sure someone would have said something.
Ride On!
08- Arcade Mechanic
TT2 laps - 4
Chuck_E_Cheese
CedarPoint150 said:
I’m not proud of the 3rd shift maintenance team for not ensuring this part was screwed on correctly. Some of the trains were making a weird “clanking” sound coming in through the brake run weeks prior to the incident. I point the finger at them. Their main job is to inspect each and every part of every train every night before signing off that it’s good to run in the morning.
You sure do sound like other people I know that does not check the oil in their own car and blame the car and manufacturer when the car breaks down. A quick study on metal and metal fatigue would be in order as well as the manufacturer recommendation on bolt strength and torque pressure and any needed documentation. It is also on the manufacturer to place a P.M. schedule on each item and how the p.m. should be preformed and documented. The sad part is that a person was injured, but there is a lot into the investigation as to why the failure happened. It could be the problem with bolt manufacturer or one or more of many circumstances. To put blame on one group of individuals like "third shift employees" is beyond absurd and not justified. Please stop the bullying and allow the process of discovery on the CP team and legal team to continue this investigation. We hope for quick closure to this event and that the victim has no life long injuries.
Sorry for the mess. Signature under construction.
RCMAC
Naw, he’s just a pissed off, second shift maintenance man.
CedarPoint150
I’m allowed to have my own justifications. I hope it wasn’t an over sight on maintenance inspections and I guess we will never know for sure… but that seems like the most logical explanation to me. I love Cedar Point so I hope that’s not the case and it was a random freak accident that couldn’t have been prevented. But yes overall I hope the investigation is closed soon, the woman heals and the ride is able to reopen safely next year.
JoshBrown
CedarPoint150 said:
I’m allowed to have my own justifications. I hope it wasn’t an over sight on maintenance inspections and I guess we will never know for sure… but that seems like the most logical explanation to me. I love Cedar Point so I hope that’s not the case and it was a random freak accident that couldn’t have been prevented. But yes overall I hope the investigation is closed soon, the woman heals and the ride is able to reopen safely next year.
Wow thats quite a different tune than your previous posts. By the way A+ job sidestepping your way past everything I said in my previous reply.
Ride On!
08- Arcade Mechanic
TT2 laps - 4
CedarPoint150
Ssssshh. Relax. The noise I heard was reported. Whether that noise had anything to do with the incident I am not sure. I’m not “slandering” 3rd shift all I’m saying is that I feel if anyone were to be able to discover the fatigued or faulty piece and replace it before falling off it would have been them as they are the main people in charge of inspecting the trains. If the piece was firmly connected the night before Sunday and it was indeed a faulty bolt that decided to give way during the middle of the day then there would have been no way to discover that unless the entire train was taken apart. Which apparently may need to actually have to happen routinely now in order to prevent something like this happening again. Who knows. The whole situation sucks big time.
djDaemon
What you are doing is the literal definition of slander, genius.
Seriously, just stop. You have no idea what you're talking about.
Brandon
JoshBrown
Please humor me and tell me how you know what 3rd shift maintenance responsiblities may or may not be. Because the kind of "inspection" you are calling for is a undertaking performed during off-season maintenance. A quick visual inspection of structure and train, along with fixing issues reported throughout the day, along with some preventative is really, to my understanding, what happens during 3rd shift. None of this would have caught metal fatique unless it was blatantly obvious or showing other signs. As someone who has worked at cedar point (albeit not in ride maintenance-but have talked with lots of ride mechanics in passing while there) and someone who deals in repair of equipment on a daily basis in my current job, i can tell you; you can thoroughly inspect as much as you want- things are still going to happen that are near impossible to catch.
Ride On!
08- Arcade Mechanic
TT2 laps - 4
0g
Regarding design flaw:
For a moment, let's assume that Dragster has some design flaw that has a one in a million chance of a metal plate being thrown from the ride and hitting someone in the queue. A very crude probability estimate would result in a 33% chance of the incident happening within the first 20 years. In other words, if there were a design flaw that had a very low probability of happening, its fully reasonable to expect that the ride could operate for 20 years without incident.
Jeff
I think at the end of the day you would have to chalk it up to "**** happens," because the odds of the failure are probably astronomically low. There's certainly some question about proximity of the ride to humans, but even then, things tend to move in the direction they're going. That this deflected off at such an angle seems even more unlikely, presumably hitting the track in just such a way to enter the queue.
Jeff - Advocate of Great Great Tunnels™ - Co-Publisher - PointBuzz - CoasterBuzz - Blog - Music
RideMan
This may have nothing to do with the incident.
When you fasten a part with a bolt (or in this case a capscrew) the bolt functions by *stretching*. So you thread the bolt into the parts (and in the case of a bolt, spin the nut onto the back) until it bottoms out, then tighten the bolt to a specified torque. Doing that actually stretches the bolt, which responds a bit like a spring by trying to return to its original length. It's that tension which keeps the bolt in place.
There are two ways that a bolt will lose torque. The first is if the bolt is loose enough that it can rotate, which obviously will allow the bolt to back out. Vibration can do this, and there are a variety of safety methods to prevent it, including thread locking material, safety wires, and various types of stop nuts. The other thing that can happen is that if the part is subject to impact loading, it can actually stretch the bolt, possibly past its yield point; that is, the point where it will not spring back to its original length. That's more likely to happen if the bolt isn't torqued properly to begin with (because if it were torqued properly, there wouldn't be any impact loading on the joint). That's what happened at Michigan's Adventure on their Chaos. The maintenance crews thought that since there was no change in the witness markings, clearly the bolts had not moved and were still tight. In fact they were loosening up until at least one bolt failed, causing the rest of the bolts to shear at once, causing the ride center to fall off of its bearing.
Now, the part we're talking about on Dragster should be subject to almost no loading whatsoever. It's not supposed to ever come into contact with anything, and if the capscrews are torqued properly (perhaps even secured with thread locker) they really should not be subject to anything that would cause them to come loose or to become at all fatigued. With that in mind, another possible conclusion can quickly be reached: that there was another failure, and that the bolts in this part failed (sheared off) as a result of the incident, not as the proximate cause of it.
The only problem with that theory is that the only thing I can think of close enough to that plate to strike it would be one of the switches...which appear to be constructed in such a way that striking one would cause the switch to fail catastrophically while doing little or no damage to a (comparatively) rather large hunk of steel.
Please bear in mind that I know nothing beyond what has been previously revealed. I'm also involved in enough other pursuits at the moment that I'm not exactly digging for details right now, either. (Anybody know a good QuickTime Pro replacement for MacOS X,XV or later?)
--Dave Althoff, Jr.
/X\ *** Respect rides. They do not respect you. ***
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DA20Pilot
djDaemon said:
What you are doing is the literal definition of slander, genius.
Seriously, just stop. You have no idea what you're talking about.
No, it's not. If anything, it would be libel.
Slander, by definition, is defamation conveyed orally.
Libel is defamation conveyed in written form.
CedarPoint150
The clanking noise I heard is in this video at 5 mins 25 seconds as the train enters the brake run.
Kevinj
But that's the purple train, unless you are implying that each of the trains have this issue (which would be even more incredible than what already happened).
Or perhaps you are suggesting it's a structural issue; in which case each of the trains would be showing some type of damage to the exact same area. If that were the case, I would think a simple visual inspection of the trains' underbellies would make something stand out. If a part of each of the trains were coming into contact with the structure on every single launch since when this video was taken (late September) I can't fathom something not sticking out.
Then again, this whole situation is bizarre, so who knows?
I don't know. If I just watched that video without any suggestion, I would just chalk up those noises to the sounds Dragster makes.
Promoter of fog.
Chuck_E_Cheese
I am in agreeance with Rideman. If the bolts were inspected by (let's say third shift) maintenance. (clears throat...) every day because they do their job better than anyone! If the bolts are to be maintained at a certain torque, and checked every day. It is possible that the bolts may become over torqued over time and the bolt may break. This is what I though when I first heard of the report that the boken bolts were still in the plate. Please correct me if I am not correct in my facts or thinking!
Sorry for the mess. Signature under construction.
JoshBrown
Tourqing a bolt requires a tool called a torque wrench. It is a specialized instrument that sets the bolt to a proper torque. For a torque check you would put said wrench on bolt (set to whatever the spec may be) if it clicks or otherwise signals the bolt is at the proper tourque, no further tightening happens. There is low probability the hardware would become "over torqued" specifically over a period of time
Ride On!
08- Arcade Mechanic
TT2 laps - 4
djDaemon
A torque wrench can definitely over-torque a fastener when used improperly, since many torque wrenches can still turn the fastener beyond the point where the wrench indicates proper torque is reached. And a fastener can be under-torqued if the friction between the fastener and mating surface produces a false positive. And then there are maintenance of the wrench - leaving mechanical torque wrenches loaded when not in use, and/or not having them calibrated at regular intervals, etc.
But yes, when used and maintained properly there is a low probability of over- or under-torquing.
Brandon
DA20Pilot
I can say from almost 2 decades of maintaining an airplane that, along the lines of what RideMan said, bolts will stretch over time from repeated torquing, even if torque is properly applied each time with a recently calibrated torque wrench, and eventually It is possible for a bolt to become fatigued from this over time. Not saying this is what happened, but seems plausible to me.
It is also possible that, if the torque wrench hadn't been calibrated recently, bolts could have been over-torqued. There are strict requirements for peiodic torque wrench calibration in aviation, but I dont know what the protocols are for amusement ride maintenance.
cp kid
Do we know what her condition is or if she is still alive?
RideMan
I would expect that the bolts in the plate we're talking about are probably not subjected to frequent mechanical torque checks. The part just isn't loaded in such a way to make that necessary. In other words, I am doubtful that the failure of the bolts was the proximate cause of the incident. I think it far more likely that the bolts failed because when an irresistible force comes into contact with an immovable object, well, something's got to give. And the bolts are probably the weakest object in that assembly.
--Dave Althoff, Jr.
/X\ *** Respect rides. They do not respect you. ***
/XXX\ /X\ /X\_ _ /X\__ _ _____
/XXXXX\ /XXX\ /XXXX\_ /X\ /XXXXX\ /X\ /XXXXX
_/XXXXXXX\_/XXXXX\_/XXXXXXX\_/XXX\_/XXXXXXX\__/XXX\__/XXXXXX
Kevinj
Since this part isn't really doing more than anything aside from "hanging on" the bottom of the car, Dave, I tend to agree.
The question is, what was the immovable object, and how to it come in contact with the irresistible force?
Promoter of fog.
jimmyburke
Does the piece in question which I believe some have called a sensor plate, align with the track rails or is it offset towards the center to align with sensors? Are there two plates, one for each side or just the one to engage with sensors? Also, what is the clearance distance, as a slight protrusion of any sort could initiate the contact. Investigators should be able to identify the first point of any impact, similar to vehicle accident investigators at a scene.
I agree it likely wasn't a nut loosening off of a bolt unless one of the two nuts loosened enough to be "almost" off of the bolt thus being able to inappropriately contact irresistable force. Not likely, just wild speculation.
Kevinj
The plate (there appears to be one on each side of the train) can be seen in this photo. It's hard for me to say how close the part comes into contact with anything.
Promoter of fog.
TwistedCircuits
Kevin that's an awesome photo! I honestly had not looked off the forums to see what part was being referred to. My best estimate looking at that picture and where those sit on the track and the following image of the station just before the launch, those are precise sensor flags for train positioning inside the station and block sections. Also looking at where they sit relative to the magnetic braking fins if one of those fins were to be out of alignment (Yes I'm aware there'd be a lot of other issues that that would cause as well) that would be the closest object I could estimate to come in contact with it.
This is all just based off of the imagery and seeing what's there but it does put a much better picture together than I've had before.
Reference picture of station because I don't know how to upload an actual image:
Still haven't been able to uncross these circuits...
DJ Fischer
jimmyburke
So, in the picture Kevinj posted we see that the plate is fastened through two holes on the vertical section of it. It appears the horizontal section is solid, with no holes. What type of stud/nut/bolt/locknut/cotter pin method is used is unknown and whether it is inserted through the track side or non-track side. As that heavy coaster comes down at 120mph and then attempts a quick deacceleration there is a tremendous amount of vibration occurring, so if clearance for that piece is minimal to begin with, any variation of an object could result in the contact.
TwistedCircuits
Now that I think about it, I'm pretty sure I've seen metal on metal contact/wear marks on the fins about that spot, this is complete conjecture on my part but Jimmy I agree and definitely see possibilities with this theory.
Still haven't been able to uncross these circuits...
DJ Fischer
Jeff
If the fins are rubbing on anything, it's on the magnets that they pass through.
Jeff - Advocate of Great Great Tunnels™ - Co-Publisher - PointBuzz - CoasterBuzz - Blog - Music
RideMan
A photo of the plate shows what appears to be a countersink on the plate (or is that just a lack of corrosion under the bolt heads? I haven’t looked at the photo in a while…) and the State statement indicated that the broken bolts were retained within the chassis which suggests to me that the bolt threads into a blind, threaded hole (so no nuts). My guess is that the bolts are probably cap screws with round socketed heads.
For the record, I have no idea what that plate might have hit (before it went flying, I mean).
—Dave Althoff, Jr.
/X\ *** Respect rides. They do not respect you. ***
/XXX\ /X\ /X\_ _ /X\__ _ _____
/XXXXX\ /XXX\ /XXXX\_ /X\ /XXXXX\ /X\ /XXXXX
_/XXXXXXX\_/XXXXX\_/XXXXXXX\_/XXX\_/XXXXXXX\__/XXX\__/XXXXXX
jimmyburke
Right, Dave, your observation of the hole possibly being threaded, with no attached nuts is possible. I'm not certain what amount of vibration that form of fastener can withstand without working loose, but it may not have worked loose whatsoever, it could have been something protruding into it's path of travel. It should not be too difficult for the investigators to locate the first point of impact, or for that matter the only point of impact. And, whether the plate was ajar or whether something within the track area was out of place such as magnets.
TTD2013
On another subject regarding the incident...what do you guys think will be the modifications Cedar Point implements to Top Thrill Dragster? Enclosing the queue/moving it could work but what if they just enclosed the brake run itself? With some sort of roof with slanted siding at least from the Finish Line to when the train is going less than 30-40 mph. Might be interesting to speculate changes before seeing what actually happens.
Also I've heard from a credible source that the woman who was hit, Rachel Hawes, is alive and out of the hospital now. This to me is amazing news because it seemed at first the degree of her injury was extremely serious to the point of life threatening.
Cargo Shorts
Like a shed?
So the flying parts can ricochet around inside as the train passes through?
TTD2013
I don't know man, lol. Just spit balling here. Something that is not too tightly enclosed but spacious enough on the inside with air vents or openings near the bottom for air flow. If any flying parts were to happen again hopefully the train would already be speeding away from it so the ricocheting part wouldn't be an issue and any guests waiting in line below would be ultimately protected. This is just an idea/one option out of many potential adjustments for the rides reopening next season.
That One Coaster Guy
When was the last time the Dragster queue was completely full? Could you shorten the overall length but enclose it with full buildings? Could have AC, angled windows every 10 feet or so that continue to give everyone views of the top, and could add additional theming into the buildings. Could be a cool way to make the queue more fun and add some theming while protecting guests.
1000 years of force
Or, perhaps, re-route the queue so that the area under the ride is devoid of paying customers?
With BOB moved to the island, that paved path and real estate could plausibly be used, with modifications, as a new not-under-this particular-ride queue.
The only thing to contend with there would be some hats falling off people riding Iron Dragon... (more than some, it turns out).
"Your persiflage does not amuse. " - Ralph (from Around the world in 80 days)
TwistedCircuits
I've thought about the reroute, how would it get back in and interface with the station away from the break run? Bridge?
Still haven't been able to uncross these circuits...
DJ Fischer
djDaemon
It's a huge stretch to assume they need to employ any mitigative strategies, given TTD has provided many, many millions of rides without this happening.
That said, a netting that can stop/redirect the object and the object's energy would be relatively trivial to implement, I would imagine. Think something like the netting used beneath lift hill stairs, only more elastic and situated vertically and strung between fence posts.
Brandon
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