Stalling Intamin "Top Hat" Coasters

Ok, so here's a hypothetical question.

Most of us have heard about the infamous Top Thrill Dragster train getting "stuck" at the top when it managed to balance its self. (http://www.youtube.com/watch?v=U9U16LtHAGg&feature=related) The stories I've heard is that this is not the only time it has happened. But regardless, it is possible for a train to balance it's self on the top of an Intamin Top Hat. Park maintenance rides the elevator up, gives it a push, and off it goes.

So I guess my question is what would, or could other parks do in the event that this scenario plays out on one of the other dozen or so coasters with a top hat, where there is no maintenance elevator to the top. This biggest ones that comes to mind are Stealth and Xcelerator. Isn't it just a matter of time before this situation plays out?

They'll send another train out to bump the stalled one.

I guess... it's more unlikely since the top hats are smaller at the top, and that the situation could be resolved by coordinated rocking and arm-waving of the passengers...

Send one worker climbing up the "up" track and one worker up the "down" track. It's like a race where the motivation comes from whichever worker gets there first pushes the train in the other direction.

That's about as likely as a train stalling on any apex on any coaster. Dragster's launch system is at fault for the trains now making it. Ask Knott's what they did when Windjammer didn't have enough speed to crest the next hill. Just bad design, the other rocket coasters are a bit easier to tame the launch inconsistencies.

You have to realize that with Dragster, there are factors that came into play that rides like Xcelerator and Stealth don't deal with.

Firstly, Dragster is MUCH taller than Xcelerator and Speed. The wind speed at 420-feet is at a higher velocity than that at 205-feet. I would not be surprised if high speed winds was a factor in slowing down the Dragster vehicle enough to enable a stall atop in that freak incident.

And also the size of the track curve at the very top on Dragster is much larger in diamater due to its greater height, which would have also contributed to that 50/50 balance at the very top. While in Xcelerator's case if the train ever came to a slowing halt at the very top, even a nudge from a few people leaning forwards or backwards could send the train going either way down with ease.

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kRaXLeRidAh said:
You have to realize that with Dragster, there are factors that came into play that rides like Xcelerator and Stealth don't deal with.

Firstly, Dragster is MUCH taller than Xcelerator and Speed. The wind speed at 420-feet is at a higher velocity than that at 205-feet. I would not be surprised if high speed winds was a factor in slowing down the Dragster vehicle enough to enable a stall atop in that freak incident.

And also the size of the track curve at the very top on Dragster is much larger in diamater due to its greater height, which would have also contributed to that 50/50 balance at the very top. While in Xcelerator's case if the train ever came to a slowing halt at the very top, even a nudge from a few people leaning forwards or backwards could send the train going either way down with ease.

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Then what about KK? What makes kk diff from dragster?

You mean other than being taller & slightly faster, and a buuny hill at the end? Mechanically, they are essentailly the same.

Do we know for certain that the Xcellerator's tophat is narrower than Dragster's? I can't really see any reason why greater height would necessitate a more gradual curve in the track, unless it had something to do with the structure needing to be wider for stability.

-Nate

Get a crane? I'm sure they have one.

I doubt any amusement park has a 250' crane just sitting around.

-Nate

This is *hardly* scientific, but I used the measuring stck tool on Google Earth and it looks like TTD is indeed wider (which makes sense given the height of the tower).

And yah, they'd probably pull out the same crane they use for Boomerang. ;)

This reminds me of the Whizzer. When it stopped on the lift, they had employees (us) push the trains to help them get started. I guess the electric motors didn't have enough torque. They normally entered the lift with a lot of help from the drive tires. Man, IO almost bought the farm doing that once...all for $3.35/hr!

Also, static friction is greater than kinetic friction (on the wheels), so in the event that a train stops moving, it is going to take more energy to knock it off than it had when it stopped.

KK has brakes at the top because it crests the tophat going faster than TTD. This is also why it has less rollbacks.

That's an interesting question... Has anyone seen XC stall?

Perhaps they just jiggle the track a little. I bet that would work.

Well SFoGswim, you are right when saying it does take more energy to get a train started if it stops on the wheels than if it is just moving past, but friction isn't the cause. There is not kinetic friction present in the wheels. The only friction associated with wheels is static. This is because at the time the wheel is in contact with a surface (ie. the wheel of your car with the road) technically that point in contact with the road is not moving. Its stationary to the road, even though the wheel is spinning.

^^ I'm referring to the contact between the wheels and the axle of the car, not the track itself.

Well, even if you are talking about where the wheels come in contact with the axle of the car, it would still be an example of static friction. There technically isn't any sliding between the surfaces. To answer why it takes more energy though is that you have to overcome that static friction. The force of static friction is an inequality, where F is greater than or equal to the coefficient of friction times the normal force. When the train is moving, there isn't the maximum amount of static friction present. But at a standstill, you must reach the greater than or equal to point to overcome the static friction. I hope that made sense.

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SFSL_Guy07 said:
There technically isn't any sliding between the surfaces.

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There very much is a sliding between the surfaces. Are you suggesting the fact that a roller coaster is completely void of any friction?

Well, if it's a Mag-lev, it might.