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Carowinds: General Discussion

Tim said:
- How did it run for a week before that was noticed. If this was in the UK (and I suspect US rules are similar) maintenance (and maybe even operations) have to walk the route of the track each morning looking for problems and obstructions. Which means that despite having been checked at least 7 times (likley more) since the crack had formed no one noticed it.
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I just watched the video. Yikes!

I can't speak for Carowinds as it varies on a state by state basis, but health and safety in the theme park and amusements industry in the USA is often completely deregulated to the parks themselves. But obviously Cedar Fair are experienced operators, so you'd hope that checks are in place to spot something of this magnitude.
 
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At the very least you'd imagine they have to inspect and test to the manufacturers own guidance for insurance purposes, even if there is no statutory duty, amd I'm pretty certain B&M stipulates exactly this. It is a bit of a shocker that the defect is visible in pics a week before.
 
Apologies for the double post but I've just noticed most the bolts connecting it to the track have been removed.
Therfore what I suspect they've actually done is welded it in place so they can unbolt it. Then both broken parts can be removed as one.
 
Alsty said:
Aren't the engineers supposed to walk and inspect the track and supports every day? You'd be hard pushed not to notice that
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I’m not sure what is typical on a ride of this magnitude. You don’t walk a steel coaster in the same way as you would a wooden ride. It’s taken them three days to crawl all over Fury, post this issue being discovered.

On rides that I have worked on, engineers would closely inspect areas where there is something mechanical, like the station, lift and brakes, but not free running track.

How this particular issue was not identified is pretty mind boggling, you almost wonder that if you have a daily battle with a Vekoma flyer, you become a little blarsé about your four B&Ms.
 
A statement from Carowinds:

"Since July 1, the park’s maintenance team and representatives from the ride’s manufacturer, Bolliger & Mabillard Consulting Engineers Inc. (B&M), have conducted a thorough inspection of the entire track, support columns and foundation. In addition, and in partnership with B&M, we have performed a battery of tests to identify the cause of the fracture, which appears to have formed along a weld line in the steel column.

Working in close coordination with B&M, we are planning to remove and replace the existing support column. The new support column, which is being fabricated by B&M, is expected to be delivered to the park next week.

Following the installation of the new column, and as part of our normal protocol for rides such as Fury 325, we will conduct an extensive series of tests to ensure the safety and integrity of the coaster. These will include an accelerometer test that uses sensors to measure any variation in the ride experience. After that, we plan to operate the ride for 500 full cycles, performing tests and inspections of the entire ride throughout that period. Once this phase is completed, we will ask B&M and the third-party testing firm to perform a final inspection to ensure the ride exceeds all required specifications.

B&M is regarded as one of the premier ride manufacturers in the world, with an impeccable reputation for quality and engineering. It’s important to understand that rides like Fury 325 are designed with redundancies in place to ensure the safety of guests in the event of an issue such as this.

While we regularly inspect the coaster, we are planning to implement additional inspection procedures to ensure we are making every effort to promptly identify and address future potential issues. These new measures will include the regular use of drones outfitted with cameras to access and inspect hard-to-reach areas.

The safety of our guests and associates will always be Carowinds’ top priority. Once the new support column is in place and all testing and inspections have been completed, we will work with the North Carolina Department of Labor’s Elevator and Amusement Device Bureau to prepare Fury 325 for reopening. We will share an update on the reopening of the ride when a date has been finalized."
 
Rob said:
Impressive that they’re getting the new support fabricated so quickly! Sounds like even with all the testing that’s going to be required, I could be back open sooner than most expected.
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*mumbles comment about opening for riders*

Back on topic though, that is a very impressive turnaround for fabrication.

Will be interesting to see if B&M release a statement at all, though I suspect not - this one has the sense of having had B&M's input.
 
Take this with a pinch of salt, but I’ve heard suggestions that the crack may have been caused by subsidence.

This would not be the first time that subsidence has occurred on a B&M to the extent of requiring support replacement (correct me if I’m wrong, but I believe Nemesis may have had supports replaced due to subsidence at some stage), and it’s not actually anything to do with B&M themselves or the original design of the ride.

As I say, take that with a pinch of salt, as I don’t know how valid the reports are, but the fact that they are fabricating a new support so soon after the crack was detected would suggest that whatever happened probably wasn’t caused by the original design itself. A clone of the existing support would likely be much quicker to manufacture than a newly designed support, as a redesign of the support would likely need considerable lead time compared to the quick turnaround that they’ve managed to pull off.
 
@Matt N I'm not picking, but in 2023 what does "I've heard" mean ?

Back in the day that meant to you had spoken to a pissed up fitter in The Star after park close who told you too much .... Now I fear it means read on another forum or some vlog nonsense ?
 
Rick said:
@Matt N I'm not picking, but in 2023 what does "I've heard" mean ?

Back in the day that meant to you had spoken to a pissed up fitter in The Star after park close who told you too much .... Now I fear it means read on another forum or some vlog nonsense ?
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Yes, it does mean what you “fear”; I’ve heard it suggested on another site I read.

As I say, take it with a pinch of salt, but that’s just what I’d read.
 
The cause could be something as simple as a poor weld. If you look closely, the crack starts at the weld and moves outwards.

B&M used to do alot of overbanked turn supports like this. Very similar in design to Fury 325's and other modern hypers, but with one key difference.
Dragon_Kahn's_Banked_Turn.jpg

The direction of the support....they are the opposite way around.
230702-north-carolina-roller-coaster-jm-1101-6feac0.jpg

It is interesting because on the first photo, the support will be under compression when a train passes, very difficult for cracks to appear and welds to fail in compression. Fury 325's support however, due to it being the opposite way around, quite literally puts the opposite force to compression on the top area of the support (where it cracked), in the form of tension. The crack has appeared at a point in the support where tension would be at it's highest, further agrivated by the fact the force from the track would be completely sideways due to the 90 degree bank. Which in turn will push more load into the diagonal support through the weld.

B&M must have a reason for doing supports like this as many modern hypers use tension supports rather than compression on their overbanked turns. Mako uses them, but the overbanked turn is more overbanked than this, so less load would be transferred to the diagonal support through the weld. So I would imagine they generate less fatigue damage as the train cyclic loads the support. That could be a potential cause, if the weld was crap.

Even our own Nemesis uses compression supports on the overbanked turn. Compression as in the train and track will push into the supports away from the track. Rather than back in on itself, like a tension support.
nemcon_jun23-02.jpg

Subsidence could be a possibility, that too will put a static tensile load / stress into the area where the crack has appeared. In addition to the dynamic tensile load as the train passes. Both would be too much for the support I would imagine. Leading to what we see here.

Whatever it is, a crack like this probably appeared very quickly, because it originates on the weld on the highest tensile stressed part of the support. That support would have been in two after less than 10 cylcic loads (trains passing over). It may have been detectable using ultrasound before it failed, but that is beyond the scope of a daily check. Once that weld failed properly, the whole thing would be cracked very quickly.

It would not say the fact they are fabricating a support so quickly is any indication of them not doing any changes. You could design a support, from scratch in a couple of hours. They are fairly simple to design and fabricate relatively speaking, lead time would not be affected as they are usually designed onsite in the same factory as fabrication.

As it is a tensile crack. On a tension support, it is possible they may strengthen the area where the crack appeared as a fail safe, even though it probably won't be needed.

I very much doubt B&M got their mathematics wrong. Which leads me to speculate that it is highly likely, subsidance, a poor weld or something else that doesn't point the finger at B&Ms legendary and usually spot on mathematics. There really is no room for the slightest error in a weld on a support you are loading with tensile stress. You could get away with it on a compression loaded support, not a tensile loaded one though because this will happen.

I think the video of the train going over the broken support, highlights better than anything, the excellent maths and engineering of B&M to be fair. I am not ruling out that they got their maths wrong, but I see that as a very unlikely scenario..
 
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Matt N said:
Yes, it does mean what you “fear”; I’ve heard it suggested on another site I read.

As I say, take it with a pinch of salt, but that’s just what I’d read.
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It is ok taking all this stuff with a pinch of salt, but I'm old, and monitoring my sodium levels is getting boring.
Big cracked steel tube, no accident, no injury, getting fixed soon.
That's all I heard, the little video was pretty though.
 
DistortAMG said:
Even our own Nemesis uses compression supports on the overbanked turn. Compression as in the train and track will push into the supports away from the track. Rather than back in on itself, like a tension support.
nemcon_jun23-02.jpg
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Perhaps I'm missing something in your explanation but this looks like a tensile load to me, with the force of the train pulling the track away from the support rather than pushing into it.

1688722425118.png
 
Alsty said:
Perhaps I'm missing something in your explanation but this looks like a tensile load to me, with the force of the train pulling the track away from the support rather than pushing into it.

1688722425118.png
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I'll use No Limits to try explain it better. See here how the track pushes into the support when a train goes over, which is braced by the diagonal support, to take of some the sideways load. The track and train is pushing a load onto the main vertical column, which in turn pushes (compresses) the load through the weld onto the diagonal column. When the train passes the track wants to move in the direction of the arrow at the top. The key takeaway is the main column is pushing the load onto the brace column, aka compression.

com2.png

Compared to this one. Once again, the track and train want to push into the same direction as above, But because the diagonal column is the other side, it has to be pulled with the main column when the load as shown in the top arrow is put on it. Instead of the vertical column pushing a load onto the diagonal column like the above for bracing via compression, it is bracing the main column by resisting the pulling force when the main column moves in the direction the train pushes it. All of this force has to all go through the weld, which is where the two columns join.
ten.png

Does that make sense? I think I've explained it badly tbf.
 
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I’ve always thought it a bit odd too that some coasters use supports in this way for exactly the reasons above. You’re pulling against the angled column, rather than pushing against it and transferring the forces into the ground. It’s always seemed a bit (quite literally!) backwards.

The only assumption I’ve ever been able to really draw from it is keeping the footprint of large elements more compact. If you have the angled brace facing inwards you’re using space that, generally only has limited use, determined by the height and train clearance envelope. Behind the track you can build pretty much anything without interfering with the coaster.

Silver Star’s car park turnaround is a good example:
IMG_5832.jpeg
 
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