Dragster Cable

Vehicles fail over time. The older they are the more maintenance that needs done. Nothing is ever a permanent fix. At the end of their useful lives, they are sold for scrap.
How long until CP sells TTD for scrap?

campfreak06 said:
Here's where I have problem. This is not the first or even 2nd time this has happened. The park knows this is an issue, fixes it, and then waits for it to happen again.

They don't just "wait" for it to happen again. They've said numerous times that they replace the cable 2 to 3 times a season to help prevent cable snaps/frays/whatever they call it. The thing is, this is the sort of thing that, I'm sure, can happen in more than one way. Hell, we don't even know what exactly happened and why (and we'll likely never know) . So it's a little unfair to suggest that Cedar Point and their maintenance team is, somehow, being negligent. If it was something specific that caused this incident, I have no doubt that they will try to prevent it from happening again.

Let's not jump to sudden conclusions without knowing the exact details.

Either way I think the negligent thing to do would be to open it as is. At the very least a taller fence should be installed at the end of the first flat section to prevent anything from being thrown forward in the event of failure.

I remember debating about uncontained failures of Dragster's cable several years ago on here.

Intamin's rocket coasters (TTD, KK, and even Xcelerator) have proven incapable of containing a cable failure when one occurs.

The force exerted by a major snap exceeds the strength of the track and trains, as evidenced by the damage to Ka and Xcelerator, respectively.

And, best case scenario when a cable failure occurs is that small amounts of shrapnel will be discharged, as was the case on TTD back when and, according to preliminary reports, now.

As I understand it, CP has focused its attention on preventing snaps- replacement and inspection intervals, water cooling, etc.

But, snaps will still happen IMO, and when they do, it is a recipe for disaster.

If we keep operating nuclear plants, there will eventually be another Chernobyl or Fukushima, it's a certainty, it's only a matter of when.

I believe the same is true for a serious injury or fatality due to an uncontained cable snap.

And, due to the nature of the the forces exerted upon the cable, I think the risk is far greater than, say, a defective wheel sneaking past inspections and causing a partial train derailment on a coaster somewhere.

I really believe the inherent danger in TTD's design is at an unacceptably high level.

Just my .02.

^Agreed. I knew it would be a matter of time before it happened again, the constant push and pull those cables go through hourly, daily, and monthly is quite a bit. No matter how often the cables are replaced, It's not as simple as refilling sidewalk or potholes when it comes to preventing this from happening again. I'm honestly surprised that the only major injury caused by these rocket coasters was a cut leg (Xelerator), but let's hope it stays that way.

The engineer in me wonders why they overlooked sufficient containment of a cable break. Was it them assuming it would never break if their maintenance and replacement guidelines were followed? Did they incorporate what they felt was sufficient pieces to contain it and keep everyone safe? That isn't something you just overlook if you ask me. Somewhere along the line there was some sort of decision made that either it wasn't needed or that minimal containment was all that would be necessary.

I'm not very familiar with the workings and design of the launch system and track and cars, but I know there has to be a solution. I feel like there has to be a way to put the cable enclosed in a channel, maybe possibly magnetize that channel to catch fragments? I'm just spitballing here, and would love a chance to look at the system up close.

campfreak06 said:

Just my humble opinion. Thoughts?

Well, you're definitely not a lawyer.

I am lost to how an act of negligence by the Soviet Union, and a cable fraying, have anything to do with each other.

I know the cable snapped in the first year of operation, but I don't think the frayed cable shrapnel incident was an actual snap. In any case, I don't think the cable failures are as dangerous as is speculated here, at least the experts maintaining the ride don't think so. And the ride has been in operation for around 13 years now, really not enough failures to make it a chronic problem.

Jeff said:

campfreak06 said:

Just my humble opinion. Thoughts?

Well, you're definitely not a lawyer.

That I am not :-) But I would like to take credit for making this thread into a worthwhile discussion!

Yikes.

Is that a good yikes, or I've earned myself a remainder of the night suspension yikes?? :-)

Now I know Dragster does not fall under the category of something a civil engineer would design, but seeing as civil engineers design things on a daily basis to withstand events on a .01 to .002 basis ( 1 in 100 to 1 in 500) I would say the odds of a ride malfunctioning like this, even on a yearly basis is around .000018 (1,000,00 riders = 55,555 trains per season) is so extreme, negligence is hardly a word to describe it. If we designed everything for every risk our world would contain next to nothing.

MichaelB said:
The engineer in me wonders why they overlooked sufficient containment of a cable break. Was it them assuming it would never break if their maintenance and replacement guidelines were followed? Did they incorporate what they felt was sufficient pieces to contain it and keep everyone safe? That isn't something you just overlook if you ask me. Somewhere along the line there was some sort of decision made that either it wasn't needed or that minimal containment was all that would be necessary.

I'm not very familiar with the workings and design of the launch system and track and cars, but I know there has to be a solution. I feel like there has to be a way to put the cable enclosed in a channel, maybe possibly magnetize that channel to catch fragments? I'm just spitballing here, and would love a chance to look at the system up close.

The containment issue is partially due to the shallow design of the launch trough. But keep in mind that the major stress is placed on cables that are on the sides and not down the middle. A lot of energy is absorbed by the cable bouncing horizontally before being ejected out the top. The snap on Xcelerator happened in a way that the cable ejected immediately and that is why it hit almost dead center on the train.

I'm honestly not sure how you could contain the system without adding a lot more parts, thus increasing the number of failure points.

Although I know that TTD is a very safe ride and that I have more chance being injured riding in a car to or from Cedar Point, the Xcelerator accident always crosses my mind when I sit in the front row.

(In fact, it has become a bit of a tradition to mention it to my friend on front-row rides once the train is in launch position. It doesn't scare him anymore, but it definitely did the first time he rode in the front.)

On another note, how is the cable set up? Is is a continuous loop, or is it like a fishing line with the train on the hook? And where do these cables usually snap in the more severe accidents? Near the catch car, somewhere down the line, or anywhere?

I believe one very heavy haul line and two smaller return cables, one each side. Rideman?

The haul line is basically a giant rubber band when that much force is exerted, and what happens when you stretch a rubber band over and over? Problem is each rubber band is different so if you replace them often enough then hopefully they don't break. However there are always those instances that lie on the edges of the bell curve and thus we have situations like this. I can change the cable daily and it will probably never fail, but is that cost effective? There is a compromise.

Problem with containment is that when you release 1.21 jiggawatts of energy, stuff happens. Containment is not really possible 100% of the time.

Here's the best technical explanation for how Dragster works.
https://pointbuzz.com/content/ttdtech

And, just for anyone who might like some reference, below is what the inside of Intamin hydraulic launch track looks like. The "C" looking channel is where the pull cables "rest" in (you can see the cables in the picture). It's also where part of the catchcar sits in (the part where the pull cables attach) :

Was there today and there were several maintenance people working on the ride with a large truck holding new cables that they were installing. I didn't know about the event that occurred last night but seeing all of those workers made us believe it wasn't opening today, not sure how soon it will be before it reopens.

If they're replacing cable, which is sounds like they are by what you said, I'd bet it'll be open tomorrow, later tomorrow or Wednesday. Of course, that is unless there's a legitimate reason they can't.

CedarPoint?

Flip it around. There are two haul cables that pull the catch car for launch and one cable used to pull the catch car back into position for the next launch. Any 'rubber band' pulling of the cables is handled by the tension wheel that's underneath the train at launch.

Judging by the pictures posted and from what I saw today, one of the pull cables either separated from the catch car, or from itself. It looks like the cables are in multiple spools and then spliced together. I'm no expert, I'm sure someone else knows better.

~Rob