The Knott's Berry Farm (KBF) Discussion Thread

[beatle11]

If for some reason, the system glitched or failed during launch, the fail safe should have meant the brakes closed slowing the train down on the launch and rolling back on the incline. On the way back down on the rollback, the brakes should have still been closed and should have completely stopped the train. As it is, that never happened.

[Tmcdllr]

^Exactly! The ride should have stopped the train completely on its own.

 

Unless this system is backwards, most if not all pneumatic braking systems use the air pressure to hold the brakes closed and springs to keep them open. With the air pressure closing the brakes this also has the advantage of being able to adjust how tightly the brakes grip so if the train does not stop in the proper place or fast enough the pressure can be adjusted to get the desired result. Unless there is a complete and total failure of the compressed air supply, there is always compressed air available to safely close the brakes due to the small storage tanks located near each set of brakes.

[thrillseaker92]

^Exactly

 

Unless this system is backwards, most if not all pneumatic braking systems use the air pressure to hold the brakes closed and springs to keep them open. With the air pressure closing the brakes this also has the advantage of being able to adjust how tightly the brakes grip so if the train does not stop in the proper place or fast enough the pressure can be adjusted to get the desired result. Unless there is a complete and total failure of the compressed air supply, there is always compressed air available to safely close the brakes due to the small storage tanks located near each set of brakes.

 

Someone correct me if I'm wrong, but I think you have it backwards... Most pneumatic breaking systems are closed when there is no pressure and require air pressure to open. It's a fail safe encase of pressure loss, so that the train will still stop even if the breaks loose pressure. There are a few coasters the other way around though, ex. Magnum XL 200...

[beatle11]

^That makes more sense to me. At least that's how it probably should be done if it's not done that way already.

[Tmcdllr]

This is how it works...(pinch type brakes)

 

The air compressor delivers compressed air to storage tanks by each set of brakes. Each tank has a regulator, which acts as a one way valve so air goes into the tanks but cannot backflow out of it. This allows the tanks to build up and store a volume of compressed air so it is always available for the brakes. The air line then goes from these tanks, through a solenoid valve, then to the brakes. Some brakes are single acting, meaning the air only closes them and springs open them. Some, like B&M or some others, are double acting, meaning air opens and closes them, so you are correct there. In single acting brakes, in order for them to open, the valve must be energized allowing the compressed air out of the brake cylinder, caliper, or rubber balloon and the springs to pull them open. When the valve is not energized, it allows compressed air to close the brakes. In double acting, the valve must energize to allow the air out on the "closing" side of the piston cylinder while at the same time allowing air into the "open" side, moving the brake from a closed to open position. When the valve is not energized, this action is reversed using the compressed air fron the storage tank to hold the brake closed. In both cases, when the valve is not energized the brakes are held closed by compressed air, which is the failsafe, if the power goes out the brakes cannot open, and can only open when the valve energizes.

 

I am not an engineer, but I have studied this system very closely and worked with ride techs maintaining these systems. This is all from memory but I believe the basic description of operation is correct. These brakes appear to be the single acting pinch type, similar to Arrow, Vekoma, and what GCI uses, using air to close and springs to open. All of those are different in design but operate in a similar fashion.

 

"And that concludes this episode of 'The Know-It-All'... Tune in next time to learn more useless and topic derailing information."

[Jay20016]

^That makes more sense to me. At least that's how it probably should be done if it's not done that way already.

 

Yeah, I always thought the failsafe on any of the brakes was that their normal state of being was closed, and that it requires some other force (air, electrical, spring, etc.) to open them to allow the train to pass. In the instance that whatever system you have goes bad, you still can stop the train.

[Tmcdllr]

Looking at the picture again, these look very similar to the pinch type that Vekoma uses, where it must inflate a "rubber ballon" inside the brake to close them and leaf springs to open. If you think about it, this makes much more sense anyway, if it used springs to close them, they would have to be giant to provide enough of a pinch to stop the train. There are no giant springs on here. Compressed air provides much greater pinch force to grab and stop a multi ton train, and can easily be increased to stop even better. 100-150 psi is a lot of force, much more than could be provided by springs. I think the confusion is most assume it's the air that opens them but when you realize the air can hold them closed, with much greater force, even when the power is out because of the reserve tanks, and the solenoid valve must be energized to open them, this system is much safer and more reliable. I used to think that too, but after observation, research, and working with the people who actually know how this stuff works, I know differently. In fact I remember years ago on Demon, one of the balloons was coming out of the trim brakes, you could clearly see it flop around when it filled up with air, was kind of funny to see, but the brake still did its job. On these brakes you can clearly see on the end where the air line connects to the rubber balloon that runs inside each brake.

 

One more thing, ever notice on this particular type of brake that you only hear the loud hiss of air escaping when they open but not when they close? There is the answer.

[milst1]

I wish the best for the injured guests, but I hate to admit that I'm feeling a bit of schadenfreude towards Knott's and Pony Express, which is a foolish attitude as a CF unitholder I know, but I'm still annoyed that they made me remove my eyeglasses (which had a retainer of course) "for safety reasons" on Pony Express at WCB this year. Never mind that eyeglasses are permitted on KK, TTD, Rita, Desert Race, Booster Bike, and other far more powerful launch coasters. I've only ever been asked to remove my eyeglasses on two occasions: After riding The Ultimate at Lightwater Valley I had to concede that I understood the request and switched to lenses for the next visit. I'll never understand the reason for the request at Pony Express, which has a top speed of 37mph. In my evil brain the accident was caused by ops management focusing on eyeglass removal instead of real safety issues.

[Tmcdllr]

^ That's exactly what happened!

 

Well at least the people who were injured seem to be ok...

BUENA PARK--A theme park spokeswoman says 10 people who suffered minor injuries in a rollercoaster accident at Knott's Berry Farm have been released from the hospital. Jennifer Blazey also said today that state inspectors, as well as the manufacturer of the Pony Express ride, will visit next week to try to determine what went wrong late Thursday. Two rollercoaster trains collided in the station where park guests board the ride when a train leaving the station didn't make it over the first hill and rolled back into another train. One person who was getting into the train and nine people who were on the train that rolled back were injured.

 

 

San Jose Mercury News

[sfmman2000]

Thanks for the information about the brakes. It will be interesting to hear what exactly went wrong.

 

The [anti-rollbacks] would only, obviously, be on the flat section to slow, then stop the train from hitting the other one.

 

Is it possible to have anti-rollbacks on a flat section of track? If the train rolled back, it seems like there would be a lot of stress on the train, as well as the riders.

[Tmcdllr]

Thats right. On a launch coaster, you would not have anti rollbacks like you would find on a traditional lift hill, as those are designed to only allow the train to go one way and hold it in place if it stops. On a launch coaster, you would find some sort of braking on the launch track, pneumatic or magnetic, to safely bring the train to a stop if it rolls back and allow the train to be backed up, or reset, to the launch position. Anti rollbacks here would not only cause damage but injury as well from the immediate stopping of the train. I suppose you could have them on the inclie of the hill, but then if the train stops there the ride is down for a long time. With the current setup, the train just rolls back down, stops on the brakes, then is reset and the ride is going again. Not to mention it is far safer to evacuate a train on the flat launch track than it is on the incline of a hill, easier too. So far i have not seen any designer put anti rollbacks on the hills of launch coasters. Maybe it would be a good idea, so if the brakes totally fail, which appears to be what happened, there would not be a collision. But these brakes are not supposed to need a backup so if these did fail, something is seriously wrong. I wonder how far up the hill it went and how fast it was going when it hit the other train.

[Jay20016]

Thanks for the information about the brakes. It will be interesting to hear what exactly went wrong.

 

The [anti-rollbacks] would only, obviously, be on the flat section to slow, then stop the train from hitting the other one.

 

Is it possible to have anti-rollbacks on a flat section of track? If the train rolled back, it seems like there would be a lot of stress on the train, as well as the riders.

 

When we're saying "anti-roll back" we're not talking about what you'd find on a normal chain lift. It is more of a "anti-roll back into the station via some form of braking"

 

TTD, Kingda Ka, any launch coaster for that matter all have some method of slowing the train in the event that it does not crest the top hat, Pony Express should be no different.

[Tmcdllr]

Since the injuries seem minor it seems like either the brakes did not stop it completely or the train was not going very fast and they did not close at all.

[Calicoasters]

TTD, Kingda Ka, any launch coaster for that matter all have some method of slowing the train in the event that it does not crest the top hat, Pony Express should be no different.

 

I don't think we are going to see Pony Express open back up with giant magnetic brake fins down the launch track.

[adamico2]

Never mind that eyeglasses are permitted on KK, TTD, Rita, Desert Race, Booster Bike, and other far more powerful launch coasters. I've only ever been asked to remove my eyeglasses on two occasions: After riding The Ultimate at Lightwater Valley I had to concede that I understood the request and switched to lenses for the next visit. I'll never understand the reason for the request at Pony Express, which has a top speed of 37mph. In my evil brain the accident was caused by ops management focusing on eyeglass removal instead of real safety issues.

 

Interesting, I was at CP a few weekends ago. They were not allowing glasses to be worn on TTD or Wicked Twister. I agree that it does seem like a silly policy for Pony Express, but they are just trying to save their butts.

[kf2010]

^^^^^Yeah tmcdllr: anti-rollbacks are more for lift hills and stop a train right where it's at in case of the lift chain snaps or stops on the lift, they don't want the train to go backward at all. The brakes on launch coasters are just "brakes" although the ones on TTD and even Pony Express differ from magnets to pneumatics.

 

So I wish someone would explain to me why hitting the e-brake wouldn't have engaged the brakes that didn't engage on their own? I doubt a whole line of brakes went out mechanically, meaning they were all frozen up. I bet this is something electrical and the proxy sensors didn't engage the brakes. In that case the e-stop would override the sensors, and would have closed those calipers manually.

 

I'm not saying it's a guarantee, but unless the entire braking system failed, I don't think it could have hurt.

[Tmcdllr]

That makes sense and e stop would close all the brakes unless they totally failed, then it would not matter.

[chadster]

so let me get this straight, based on the theory of air pressure being required to close a break as has been suggested, then the break would no longer be fail safe as any cut in a line, loss of pressure in the tank, cut in the bladder, would then cause a serious failure in the system. A semi truck for example, uses air pressure to hold the breaks open, any loss in pressure, line cut, or bag cut, clamps the break tight, hence, fail safe. Just imagine the loss of air pressure during breaking after a 65mph run, the results would be devistating. Air compressors can fail, lose electric, line connections blown apart, etc. etc. the failures using a system that requires a break to have air pressure to close are almost endless, but not usually a reality, which is why I prefer the breaking used on patriot and prowler, plus its way smoother than hitting a hard break run. So in this particular setup, I'm trying to figure out where the 100% fail safe point is, that's all.

 

Patriot has two magnetic breaks that slow the train before the breaking near and on the transfer tracks which uses a traditional air powered caliper style break. When the computer senses the ride has slowed enough, it retracts the mag breaks to allow the ride to continue to pass then puts them back in place for the next train. Prowler appears to be using a similar, but not exact, type of system. I'm hopeful that the advances in technology will allow this type of breaking combination to be used on all new designs, plus I would imagine it would be less wear and tear on the ride.

 

all of that aside, and I'm not saying anyone is wrong, then the calibration on this style of break could have been so far off for the ride to not stop, that even an estop might not have helped.

 

Here's a cool site to check out

[Guy T. Koepp]

^That was a very cool read.

[chadster]

October 08, 2010|By Brady MacDonald | Los Angeles Times Staff Writer

State investigators have conducted an initial investigation of a roller coaster accident at Knott's Berry Farm that injured 10 riders, theme park officials said.

 

All the injured riders were released from the hospital Friday, the day after the Pony Express horseback-style launch coaster failed to make it up an incline and rolled back into the loading station, slamming into another train waiting to depart, said Jennifer Blazey, spokeswoman for the Buena Park theme park.

 

Ride manufacturer Zamperla, which is based in Italy, released a statement saying it would fully cooperate with the ongoing accident investigation by the California Division of Occupational Safety and Health (DOSH).

 

A Zamperla representative will visit Knott’s to investigate whether any "programming problems" led to the accident, Blazey said.

 

Next week, DOSH investigators will look at the mechanics of the ride, attempt to isolate the malfunction, review the ride’s maintenance records and interview ride operators, said Dean Fryer, spokesman for the DOSH amusement ride unit.

 

Investigators will be looking at whether the Pony Express track featured an anti-rollback mechanism or a zone protection system designed to keep trains running on the same track separated, Fryer said.

 

The relatively mild coaster, designed for the 'tween set, reaches a height of 44 feet and a speed of 38 miles per hour over an undulating, figure-eight course. Riders straddle the saddle-like coaster seat like a horseback rider. An automated restraint system presses against the rider’s lower back, providing little support for the shoulders and neck.

 

The ride will remain closed until the state investigation is completed, Blazey said, adding that the train waiting in the station was damaged in the accident.

 

In September 2009, a cable snapped on the hydraulically launched Xcelerator coaster at Knott's, spraying debris that injured two riders. A state investigation blamed the Xcelerator accident on both Knott's and the ride manufacturer, Switzerland-based Intamin AG.

 

I found comical that " Investigators will be looking at whether the Pony Express track featured an anti-rollback mechanism or a zone protection system designed to keep trains running on the same track separated" shouldn't they have done that prior to permitting the ride?

 

link

[Tmcdllr]

so let me get this straight, based on the theory of air pressure being required to close a break as has been suggested, then the break would no longer be fail safe as any cut in a line, loss of pressure in the tank, cut in the bladder, would then cause a serious failure in the system. A semi truck for example, uses air pressure to hold the breaks open, any loss in pressure, line cut, or bag cut, clamps the break tight, hence, fail safe. Just imagine the loss of air pressure during breaking after a 65mph run, the results would be devistating. Air compressors can fail, lose electric, line connections blown apart, etc. etc. the failures using a system that requires a break to have air pressure to close are almost endless, but not usually a reality, which is why I prefer the breaking used on patriot and prowler, plus its way smoother than hitting a hard break run. So in this particular setup, I'm trying to figure out where the 100% fail safe point is, that's all.

 

Patriot has two magnetic breaks that slow the train before the breaking near and on the transfer tracks which uses a traditional air powered caliper style break. When the computer senses the ride has slowed enough, it retracts the mag breaks to allow the ride to continue to pass then puts them back in place for the next train. Prowler appears to be using a similar, but not exact, type of system. I'm hopeful that the advances in technology will allow this type of breaking combination to be used on all new designs, plus I would imagine it would be less wear and tear on the ride.

 

all of that aside, and I'm not saying anyone is wrong, then the calibration on this style of break could have been so far off for the ride to not stop, that even an estop might not have helped.

 

Here's a cool site to check out

 

Nothing is failsafe but in order for a braking system like that to totally fail, the main compressor would have to go down, every tank by every brake woulds have to lose pressure or there would have to be a leak at every set of brakes. All of that happening at the same time is near impossible, unless the pressure is released from all the tanks or the rubber balloons are cut, which again is near impossible since they are really thick rubber and are inside the brake, the brakes will still close. There is your failsafe.

 

I agree about magnetic brakes, besides slowing the train a lot more smoothly there is really nothing to fail on them, unless they retract and don't move back to a braking position. But these and even the fixed magnetic brakes are far better and never wear out or require adjustment for the most part. Maybe Zamperla felt, for whatever reason magnetic brakes would not be a good idea here, I don't know why, they seem to work just fine on Intamin launch coasters. I'm thinking with this accident either the brakes did not close at all due to a sensor or PLC malfunction, or they did close but for whatever reason did not close tightly enough to stop the train. From what I remember from the pic it looks like there are two pairs of brakes on the launch track, four total, even if only one or two of those closed it should have been enough to at least slow the train to a stop well before it got near the station. In that case its possible they were not in proper adjustment or very worn, who knows. I just wish they would hurry up and figure out what happened.

[AJClarke0912]

I know this sounds really stupid, but what if the brakes system was living on Opposite Day? I mean, during the launch sequence they could have been closed (reason for not clearing the hill) and open on the way back (thus colliding the train). Some computer programming screw-up? Could be. Just thinking out loud though.

[Tmcdllr]

Opposite day... Lol!

[Guy T. Koepp]

The only problem with your opposite day theory is that if that was the case, then every launch would have been a roll back except for this one. There by avoiding the accident in the first place.

 

Guy "Yeah! Blew that theory out of the water!" Koepp

[cfc]

^Thank you, Dr. Science!