Serious accident on Xcelerator caputerd on Video

crazy horse said:
I also had an issue with the "no eyeglasses" policy on this ride.

It's a Knotts thing. Amazingly they won't allow secured eyewear on the Pony Express either, which is a much slower launch. Really put me off the park TBH.

Lord Gonchar said:
The video has been removed from youtube.

Seems to be available now, I just found it a moment ago.

I *am* curious as to how debris like this could cause back pain though. It strikes me that the back should be fairly well protected if one is sitting correctly.

^ The shock that knocked the boy's seat up and to the left could quite possibly cause a back issue if it slammed you in the spine. He clearly gets jolted up when the seat dislodges, and if I'm not imagining things, it almost seems as if he is pinned between the (non-moving) bar and the (moving) seat when the ride comes to a stop because the lapbar doesn't appear to move in relation to the camera but the seat does without doubt.

Yea... this accident isn't serious or anything...., a little boy was only whipped in the leg by a cable powerful enough to cut someone in half, and then his seat starts to disconnect squeezing him between a stable lapbar and a moving seat. Sounds pretty serious and awful to me, even ignoring the unknown debris that clearly gets sprayed into their face/eyes.

How the heck did the seat come loose like that, anyway? Cable must have hit that train pretty hard.

I haven't done the frame by frame analysis that Dave has, but it sure looks like that seat moves relative to everything else in the frame to me.

Edited to add:

On the notion of major vs. minor---I suppose you could argue minor if its just the small debris cloud. But if the integrity of that seat was compromised, there is no way to call it anything but major in my book.

Based on what I've seen so far, I won't be getting back on any of the Intamin rockets (and neither will my kids) until the DOSH report is published, at the very earliest. That report is going to be very interesting.

I feel so bad for that kid, CF maintenance is really good though, and the cables are super strong, and super durable. Dragster ran after a cable mis-spooled for a week during a season and it was ok, the cables just break sometimes. I can't tell which parts are cable and which parts are shards of the train. Either way it's good that the kid only got a little cut, but beyond that the launch mechanism is really safe, the only way to even see the cables in the actual launch track is to stick your head way down in there. Does Knott's cool there launch cables like Dragster does, I know CP had to install a special water cooling system because the cables got hot and stretched out and broke.

I think you misunderstood the purpose of the water system... it's there to reduce the friction of the launch sled running over the channel, not for cooling the cable.

Edit: just noticed something... on Knott's site, the rehab schedule (look at the lower right column) lists Xcelerator as being closed for scheduled maintenance from September 17-30. Is this the only rehab the ride has every year? If so, it's quite interesting that the cable broke just before I'd imagine it's replaced (judging by the other posts that say the cables are replaced yearly). This accident would be even more tragic if it turned out that the ride was due to be closed, but the park decided to keep it open for one last weekend...

Hmm, I might be wrong. Maybe the maint. guys who told us that were just making stuff up, they've done that before, the touch screen warnings about cable cooling water flow were tied into the water pressure of hoses that emptied into the cable troughs and not the catchcar trough which is encased in plastic but I haven't been there for forever, so I might be mistaken.

I was able to see the engine room after the cable snapped on Dragster and I think everyone involved in this accident is very lucky the injuries were so minor. A 3-inch deep slice into pure concrete is pretty heavy stuff.

The ride was not supposed to get into rehab until december. The 9/17-9/30 rehab schedule has been added after the accident to the Knotts Website. Expect it to be "updated" to a later ending date

This is an extremely scary accident...I can't even imagine sitting in those front seats while this was going on.

Am I the only one thinking that if Xcelerator utilized Intamin's OTSR's (which tighten considerably when the train is launched), the boy's legs/waist would have been completely crushed when the seat jammed forward? Makes you glad that this particular accident didn't occur on Storm Runner or KK...

There is nothing "pure" about concrete, by definition. :)

Getting back to the video for a moment, I think we see two debris clouds at two distinct portions of the video. The first is just as the train disengages from the catchwagon, and everything in that debris cloud appears to be very small. I expect this is probably fragments of the haul rope, but I would sure like to know what causes the broken rope to disintegrate into fine pieces, and furthermore why does that shrapnel go airborne for the train to go blowing through it.

The second debris cloud happens at the top of the hill, just as the train stops. My suspicion is that this is pieces of the nose of the train...that is to say, bits of Fiberglas that had probably been flying along with the train until everything kind of ran out of energy at the top of the hill.

What I find interesting about this incident is how little we actually know about what happened, considering that the one bit of evidence we have (aside from the park's statement) is a piece of video of the incident actually happening. We really know very little about what happened. We know the train went through a cloud of debris, and we know it went through a second debris field which was probably related to the train itself. We know that at the point of failure, about where the first debris field was, that there was something there that looks like smoke. We know from reports that both the people we saw were injured badly enough to require hospital treatment, and that one person was admitted for a day and a half or so. We know that one of the injuries was a laceration to a leg, but in spite of the comments in this thread, we do not know the mechanism of injury. We presume that the haul ropes failed, but we don't have any real evidence of that, we don't know where the failure happened, and we don't know where the ends of the rope went after the failure.

In short, we know that Bad Things happened on Xcelerator. We actually got to watch Bad Things happen on Xcelerator, but from the video, we still don't really know a whole lot about what actually happened! I just find that to be a very interesting paradox. Kind of like watching a Penn & Teller trick.

--Dave Althoff, Jr.

Oops, forgot to mention...

That the impact, if I may use that word, of a severed haul rope on the train would be limited but could be rather severe on the motor house is not surprising, and is by no means a stroke of luck. One of the things Intamin actually got right with this system is that if the haul rope fails, the drive system should be pulling the tensioned end •away from• the riders at terrific speed. That should protect the riders from the rope end, but once the broken end comes through the sheaves and enters the motor house, it can really do some damage...!

--Dave Althoff, Jr.

I wonder about that, Dave. At the perceived point of failure in the video, I think it's safe to assume that the motor would have started to decelerate, right? And if only one of the two cables broke, the broken one will continue to move forward with its momentum, and since it's not going to move in a nice linear motion down the channel and spill out in front of the motor house, I suspect it would bunch up and come out of the channel. What do you think?

PhantomTails said: on Knott's site, the rehab schedule (look at the lower right column) lists Xcelerator as being closed for scheduled maintenance from September 17-30. Is this the only rehab the ride has every year?

Both Xcelerator and Ghostrider have two 2-week closures for maintenance: just prior to the Winter Solace event and just prior to Haunt.

RideMan said:
Someone said something about the mobility of the train after the incident...we know that the train is mobile following the incident because it did in fact over-run the catch car and went up the hill, then rolled back into the brakes. So releasing the brakes should allow the train to continue to roll back to the station.

That was me. And, what I meant was that we don't know if the train was still mobile after the train came to a stop. Since we don't know the full extent of what happened, it's possible that there was debris preventing the train from going any farther back. I'm not familiar enough with Xcelerator to know if where that stopped was where a roll back is supposed to stop. Think of it like an engine that seizes. It was moving along fine until it stopped. And once it stops, there's very little chance it's going to move again. Maybe not the best example, but you see what I was getting at.

On another note, I have been out of the loop since shortly after this thread started. I just finished reading all the posts. And though I agree with Dave on almost every point, I also think the seat moved in some manner.

tambo said:
All I could picture here was Kevin Costner's courtroom scene in JFK dissecting the Zapruder film for the jury. "Back, and to the right. Back, and to the right. Back..."

The only thing missing was a "Magic Bullet". :)

I know this isn't a situation to be made lite of. But, when I read that, I almost spit out my beer from laughing.

^I was curious about the train stopping as well. I imagine most of us have seen a rollback, and, in normal operation the train crawls back down the launch track until it hits one of the tires. I have only seen Dragster and Stealth rollback, so I can't speak for Xcelerator, but I assume it's the same. As such, I'm still wondering what caused the train to come to its final and sudden stop.

IntaminHater said:
You obviously would think this is thought about in the engineering process, but you forget that this is a ride manufactured from the most irresponsible Roller Coaster engineering company in the world today. The saddest part is that these types of accidents have become something regular from this company, and no one seems to care enough to put a stop to the madness. For whatever reason parks keep purchasing from a known poor manufacturer that has a very high injury/death rate comparatively to other companies, and they never take responsibility. All you Intamin fans can continue to close your eyes to the facts or you can wake up and see reality....

I wouldn't necessarily argue that it's "irresponsible" engineering. I believe, and know for fact, the problem is their systems are designed primarily In Theory. This is evident in the consistency of problems that arise in their mechanical and electrical systems, not just on the major installments in the past decade, but in roughly all of their modern design work. Many of the products we've all seen them produce have been prototypes. ...somewhat of a factor thats spawned this era of rides.

Additionally, associated warranties or manufacture policies tend to expire after a specific point or go void following general maintenance performed incorrectly(it happens more often then you'd think) - therefore legally taking the fault off the manufacture. In the design of a system with high stresses, especially ones that "wear n tear" this consistently, these risks are calculated. We all understand how these systems work, and with that understanding, we tend to gain an interest in general mechanics, physics, engineering. And in time learn how simple systems work. Knowing that, One would easily understand, this is technically a 'common' error. Timing in this case was just a misfortune. These type of events even happen on machinery as complex as Aircraft Carriers, and take into account the amount of thrust + accelerating mass is riding on that pusher car, that would increase the odds of stress overload far greater than any simple system in the rocket coasters.

To Keep it simple: A Calculated risk happened with bad timing.

The real question is has anyone been to the park since then? I find it hard to believe that photos of the aftermath haven't yet surfaced.

Someone said the catch car should push the train, one way or another a cable would have to be infront of the train as it has to connect to the machinery in front of the launch track. A cable could snap at any place, and where that cable goes depends on where it snaps...