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Ultimate Rollercoaster > Discussion Forums > Roller Coasters, Parks & Attractions > A Technical Query About Rollbacks

A Technical Query About Rollbacks

Posted: 7/9/10 at 1:40:24 PM
Views: 5310

For those of you who have have experienced a rollback, seen one, or simply know what you're talking about more than I do (isn't that everybody?)...If a rollback occurs on TTD or KK, after nearly reaching the top, it's obviously designed to roll safely back down to re-launch. But are there any brakes on the way back down the tower? Or does the train not get slowed until reaching the launch track,where there may be another train waiting to launch?

Mike, whose only rollback came on a ten-foot high junior Dragon Coaster last November...

Re: A Technical Query About Rollbacks by Shaggy Shaggy Profile at 7/9/10 2:46:33 PM

I've seen a rollback on TTD. I'm no expert, but this is how I visually understand the workings of TTD.

If the train does not crest the hill, and rolls back, then there are magnetic brakes on the launch track that slow it to a crawl. There are no brakes on the incline.

Before a train launches on TTD, it rolls out of the station and enters the launch zone where it adheres to the catch car mechanism on the steel launch cable. It cannot enter the launch zone until the sensors at the top of the track have indicated that the prior train has crested. As the train stops on the launch track, it is weighed and the internal computers calculate the torque needed to pull the steel cable fast enough to crest the train. During this time, the train is slightly rolling backward to lock it onto the catch car. At this point, there are magnetic brakes raised along the launch run that remain elevated until the cars computer processing is complete.

Once the computer readies the launch, the brakes (which are on hydraulic pistons) are lowered beneath the launch run. The train then launches. When it passes the various brake "sections" they raise immediately as a safety stopping feature should the train not crest. There are several "stations" of brakes, so should one section not raise... the others are there as a back up. The hydraulics default to the "up" position. Meaning should electrical fail or such, the brakes remain up. IOW the hydraulics lower them... not raise them.

When a train rolls back and hits the brakes, they slow it to an absolute crawl. It takes several minutes for the train to even make it back to the launch section... like 10 or so (from what I recall.) At this point, the determination can be made as to re-launch, re-set or close the ride.

Does that help?

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Re: A Technical Query About Rollbacks by RobLec RobLec Profile at 7/9/10 2:48:00 PM

There are brake fins all along the launch track. You can see, hear, and feel them retract just before the next train is launched.

Re: A Technical Query About Rollbacks by beastmaster beastmaster Profile at 7/9/10 3:11:00 PM

> I've seen a rollback on TTD. I'm no expert, but this is how
> I visually understand the workings of TTD.

> If the train does not crest the hill, and rolls back, then
> there are magnetic brakes on the launch track that slow it
> to a crawl. There are no brakes on the incline.

> Before a train launches on TTD, it rolls out of the station
> and enters the launch zone where it adheres to the catch
> car mechanism on the steel launch cable. It cannot enter
> the launch zone until the sensors at the top of the track
> have indicated that the prior train has crested. As the
> train stops on the launch track, it is weighed and the
> internal computers calculate the torque needed to pull the
> steel cable fast enough to crest the train. During this
> time, the train is slightly rolling backward to lock it
> onto the catch car. At this point, there are magnetic
> brakes raised along the launch run that remain elevated
> until the cars computer processing is complete.

> Once the computer readies the launch, the brakes (which are
> on hydraulic pistons) are lowered beneath the launch run.
> The train then launches. When it passes the various brake
> "sections" they raise immediately as a safety
> stopping feature should the train not crest. There are
> several "stations" of brakes, so should one
> section not raise... the others are there as a back up. The
> hydraulics default to the "up" position. Meaning
> should electrical fail or such, the brakes remain up. IOW
> the hydraulics lower them... not raise them.

> When a train rolls back and hits the brakes, they slow it
> to an absolute crawl. It takes several minutes for the
> train to even make it back to the launch section... like 10
> or so (from what I recall.) At this point, the
> determination can be made as to re-launch, re-set or close
> the ride.

> Does that help?

Sure does..Thanks! Now I just gotta get one! Based on your explanation, I wonder if the operators can DECREASE the force of the launch in order to INCREASE the chance of a rollback. I guess that's conceivable...but no operator would ever do THAT, would they? ;-)

Mike

Re: A Technical Query About Rollbacks by Shaggy Shaggy Profile at 7/9/10 3:24:26 PM

The ride operators have no control over whether the train rolls back or not. They cannot increase or decrease the speed of the cable/train.

Shaggy

Re: A Technical Query About Rollbacks by beastmaster beastmaster Profile at 7/9/10 3:28:59 PM

> The ride operators have no control over whether the train
> rolls back or not. They cannot increase or decrease the
> speed of the cable/train.

> Shaggy

Ah. Gotcha.

Mike

Re: A Technical Query About Rollbacks by shawnnash2005 at 7/9/10 3:29:01 PM

So would'nt superman the escape at sfmm be kind of the same as a rollback on ttd or kk?

Re: A Technical Query About Rollbacks by GoYanks34 GoYanks34 Profile at 7/9/10 5:01:04 PM

Shaggy - Very nice explanation - thanks for taking the time to explain that so well!

One more question: Since the car is weighed to determine the power needed to launch it, is it conceivable that some launches could be faster or slower, or is the speed the coaster is supposed to go pretty much always achieved? I ask because on both TTD and KK there are times it feels faster or slower on different rides on the same day. I'm sure where you're sitting and wind speed have something to do with the perception of the speed you're going but I was wondering if the speed does actually vary as well.

Thanks!

Jen

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Re: A Technical Query About Rollbacks by RobLec RobLec Profile at 7/9/10 7:11:12 PM

> The ride operators have no control over whether the train
> rolls back or not.

Upon first opening in the morning they run a reduced load until the ride warms up, generally starting with only the front half of the train, then adding a row of riders after each successful launch.

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Re: A Technical Query About Rollbacks by SFGAman SFGAman Profile at 7/9/10 7:48:08 PM

I don't know much about rollbacks but i do know that the brakes are in the launch section and not coming down the tower.

Rollbacks are usually caused by not enough speed when the cable launches the car, but on rare occasions a cable can snap during a launch which can be very harmfull to the riders.

Take this video for example. It was on xcelerator and it looks bad if you look at mor pics and videos of the accident.

http://www.youtube.com/watch?v=6EGHHjN0bQs

Re: A Technical Query About Rollbacks by KHTOExtreme at 7/11/10 7:09:50 PM

This is from there blog.

http://http://www.cedarpoint.com/public/fun/blog/2006/6/12/Behind_The_Rides%3A_Top_Thrill_Dragster.cfm

Re: A Technical Query About Rollbacks by KHTOExtreme at 7/11/10 7:11:03 PM

Part 2

http://http://www.cedarpoint.com/public/fun/blog/2006/6/16/Behind_The_Rides%3A_Top_Thrill_Dragster%2C_Part_Two.cfm

Re: A Technical Query About Rollbacks by JALLLL JALLLL Profile at 7/11/10 9:43:26 PM

> For those of you who have have experienced a rollback, seen
> one, or simply know what you're talking about more than I
> do (isn't that everybody?)...If a rollback occurs on TTD or
> KK, after nearly reaching the top, it's obviously designed
> to roll safely back down to re-launch. But are there any
> brakes on the way back down the tower? Or does the train
> not get slowed until reaching the launch track,where there
> may be another train waiting to launch?

> Mike, whose only rollback came on a ten-foot high junior
> Dragon Coaster last November...

Dude!!............if this coaster rolls back while on the lift hill you are done.......dead!!!!!!!!!!!!!

That is why the park, pays heavy on life insurance for any rider on this coaster.

The park found it to be cheaper, if they just pay higher insurance rates, then come up with some heavy expensive anti-rollback device.....so if you ride this coaster............do it at your own luck.

Re: A Technical Query About Rollbacks by GoYanks34 GoYanks34 Profile at 7/12/10 12:31:43 AM

> For those of you who have have experienced a rollback, seen
> one, or simply know what you're talking about more than I
> do (isn't that everybody?)...If a rollback occurs on TTD or
> KK, after nearly reaching the top, it's obviously designed
> to roll safely back down to re-launch. But are there any
> brakes on the way back down the tower? Or does the train
> not get slowed until reaching the launch track,where there
> may be another train waiting to launch?

> Mike, whose only rollback came on a ten-foot high junior
> Dragon Coaster last November...

> Dude!!............if this coaster rolls back while on the
> lift hill you are done.......dead!!!!!!!!!!!!!

> That is why the park, pays heavy on life insurance for any
> rider on this coaster.

> The park found it to be cheaper, if they just pay higher
> insurance rates, then come up with some heavy expensive
> anti-rollback device.....so if you ride this
> coaster............do it at your own luck.

What the hell are you talking about? Half of your post doesn't even make any sense. Rollbacks happen all the time and no one is dead or even injured for that matter from them. Actually, most people enjoy them and/or would like to experience one, so before you start typing nonsense, know what you're talking about first.

And parks do not have life insurance on people either, that's not even possible - they carry liability insurance.

Jen

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Re: A Technical Query About Rollbacks by hersheyworker hersheyworker Profile at 7/15/10 11:56:27 PM

Lol if everyone died on rollbacks every launch coaster would be closed by now.

Re: A Technical Query About Rollbacks by Cyclone_Phil Cyclone_Phil Profile at 7/16/10 12:27:09 AM

Plus a recent Travel Channel show recorded an actual rollback with the host on it. I guess he must be a zombie now? :)

Re: A Technical Query About Rollbacks by GoYanks34 GoYanks34 Profile at 7/16/10 12:29:49 AM

> Plus a recent Travel Channel show recorded an actual
> rollback with the host on it. I guess he must be a zombie
> now? :)

LMAO! I can see the next George Romero movie now: Night of the Zombie Travel Host

Jen

Re: A Technical Query About Rollbacks by beastmaster beastmaster Profile at 7/16/10 5:27:48 AM

> Plus a recent Travel Channel show recorded an actual
> rollback with the host on it. I guess he must be a zombie
> now? :)

> LMAO! I can see the next George Romero movie now: Night of
> the Zombie Travel Host

> Jen

Well, there IS an enthusiasts club called Coaster Zombies in existence now..I guess they could be extras.

Mike

Re: A Technical Query About Rollbacks by Absimilliard Absimilliard Profile at 7/17/10 12:25:38 AM

To add to your explanation about how the blocking systems, Xcellerator has a very bad set up for that.

Basically, on Xcellerator, the second train on the track cannot enter the station until the other train has entered the first overbank turn. The result for that is that in the case of a rollback, the only place for that train to park is the station. On Kingda Ka, Stormrunner and others, there is a spot where the train can park before the station and in the case of Kingda Ka and TTD, two.

When Tussaud ordered their two Rocket from Intamin, they solved the issue of Xcellerator by adding an unload position in the station.

Re: A Technical Query About Rollbacks by SFGAman SFGAman Profile at 7/18/10 11:51:00 AM

Of of what JALLLL said ther is probably no chance you will not be harmed on a rollback with a chain...and it almost never happens too.

-SFGAman who has never been in a rollback...

Re: A Technical Query About Rollbacks by beastmaster beastmaster Profile at 7/18/10 11:58:01 AM

> ther is probably no chance you will
> not be harmed >

"NO chance you will NOT be harmed" really means there's a GOOD chance you WILL be harmed.

Double negative turns it into a positive. But thanks for the tip. I'll keep it in mind if I ride Kingda Ka next Sunday...

Mike

Re: A Technical Query About Rollbacks by SFGAman SFGAman Profile at 7/18/10 1:37:45 PM

^^^^^sorry typo

Re: A Technical Query About Rollbacks by Judy_P_in_Pgh Judy_P_in_Pgh Profile at 7/18/10 2:06:58 PM

I'll keep it in mind if I ride Kingda Ka next
> Sunday...

IF?

Re: A Technical Query About Rollbacks by JALLLL JALLLL Profile at 7/18/10 10:08:24 PM

Most rollercoasters (if not all) have rollback devices on the Lift-Hill..........

No need to worry about this small stuff..........go ride and enjoy coasters!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Re: A Technical Query About Rollbacks by alpengeistno3 at 7/19/10 3:19:32 AM

> Most rollercoasters (if not all) have rollback devices on
> the Lift-Hill..........

> No need to worry about this small stuff..........go ride
> and enjoy
> coasters!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Not all. Obviously, shuttle coasters don't (got to get back to the station somehow), and a lot of single train kiddie coasters don't. I saw Blackbeard at Great Adventure roll back 3 times on opening day last year.

And I believe you MEANT "Anti-rollback devices" (however, I do believe Vekoma Boomerangs are equipped with an actual rollback device for the 2nd lift.)

Paul

Re: A Technical Query About Rollbacks by Absimilliard Absimilliard Profile at 7/19/10 1:07:14 PM

There is no anti rollbacks on the Boomerang second lift hill. The loud noise when the train engage it are the chain dogs under the train jumping loudly over the slower moving chain.

Many coasters using pinch wheels on the lift hills do not have separate anti rollbacks.