The strenth of up-stops

Are up-stop wheels designed so that they are strong enough to hold a train to the track, in the case that the train should get stuck in an inversion? Let's say that one of the wheel chassis ( sp? ) on Viper at Six Flags Magic Mountain broke and the train was stuck upside-down in the middle of the first loop. Would the up-stops be able to hold the train to the track, or are they only good for a certain weight?
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They can take the load of the train and then some.

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Yeah on arrow loopers i think the upstops are exactly the same size as the road (running) wheels so they could most likely hold the exact same weight

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See Demon, SFGAm, like 3 years ago. The upstops held the train in the loop for hours.

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Demon @ SFGAm (Same coaster company, and another looper) Got stuck in a loop a few years back. Held tight.... no problem there.

Edit: Den beat me =(

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« adix@nedesigns.com »

* No one cares about your post count *
*** This post was edited by Adix 2/4/2003 10:17:07 PM ***

UltimateFlightNJ said:
Yeah on arrow loopers i think the upstops are exactly the same size as the road (running) wheels so they could most likely hold the exact same weight

While I agree that the trains should be able to hold themselves upside-down, I don't think wheel size is really the cause. More the strength of the wheel assemblies.

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Be polite and ignore the idiots. - rollergator
"It was like that when I got here."
"I'll procrastinate later."

Yeah,the demon incident occured back in 98 & the train was stuck mid loop for over 2 hours & it held just fine.

The cause of the incident was because one of the road wheels on the last car of the train broke off resulting in the train getting stuck in the worst possible position.

Didn't Shockwave loose a wheel last season as well? that's probably what led to it's removal for S:UF instead of Whizzer along with protests against Whizzer's removal.

Just want to clear something up: Upstops are most definetly not the same size as road wheels. In addition, (on Arrow coasters), there is only one of them per wheel assembly, while there are two road wheels (and guide wheels, for that matter).

That beeing said, they can ( and do) support the weight of the train. Arrow and Vekoma coasters usually have some space between the upstops and the track, which means that the upstops are the only thing keeping the train from hurtling off the track in moments of airtime (which actually exerts more force on the wheels than the resting weight of the train ). Also, as has been pointed out, several cars on the Demon where supported mainly by their upstops for several hours in 1998. How they do this, being so few in number and so small, is beyond me.

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*** This post was edited by (SF)Great American 2/5/2003 12:23:00 AM ***

I'm not so sure that any arrow looper gets more than -1G (which is what is implied by more force than the resting weight of the train). Unless you're referring to the fact that there's only one instead of two, but I still don't think most Arrows hit -0.5G either.

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Be polite and ignore the idiots. - rollergator
"It was like that when I got here."
"I'll procrastinate later."

Hmm... You could be right about that... I was thinking more along the lines of their hypercoasters, which pull some insane airtime. But their loopers really don't...

Regardless, the upstops are smaller than the road wheels (although there are only one per assembly on the hypers), and withstand a lot of force. Even if it's not one full G (which I'm pretty sure it is), I'd think that they would be engineered to stand up to more than the ride's supposed to subject them to.

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I hear America screaming...

We were always taught to build structures with a factor of safety of 3 or greater. I would assume that the upstops can support 3 times the weight (force) it normally encompasses

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(SF)Great American said:
Just want to clear something up: Upstops are most definetly not the same size as road wheels. In addition, (on Arrow coasters), there is only one of them per wheel assembly, while there are two road wheels (and guide wheels, for that matter)

There is at least one example where this is not the case. SUF upstops and road wheels are the same diameter (12 inches). Of course, it runs on those upstops through the pretzel, so it only makes sense they are the same size.

Just thought I would point that out. ;)

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Yeah, well, B&M can be weird like that...

Thanks for pointing that Out. I will add that fact to my store of useless knowledge.

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I hear America screaming...

Yeah... and I should point out it's the only one like that I know of. Well, I'm sure the other two SUFs will be like it also.
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Sirocco (Schwarzkopf shuttle) at Walibi Wavre (now known as Turbine at Six Flags Belgium) got stuck halfway through the loop in July 97 after the launch failed. Riders were only held in the train by lap bars.

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*** This post was edited by Invy 2/5/2003 3:43:55 AM ***

The Flyers don't really have upstop wheels... since the cars run right-side-up half of the time and upside-down half the time, they need two sets of road wheels http://rcdb.com/installationgallery920.htm?Picture=2

The reason Arrow upstop wheels are smaller is because they aren't used much while the ride is in operation - only a couple of seconds when there is airtime. The road wheels are larger so they get less wear (the same reason Millie or SUE have huge wheels... the larger the wheel, the fewer rotations.)

As was stated earlier by ApolloAndy - the strength is in the wheel assemby.

The Vekoma Flying Dutchman also have the same size wheels on both top and bottom like the B&M flyers.

http://www.rcdb.com/installationgallery920.htm?Picture=2

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Photographer
www.pkiunlimited.com

Look... B&M calls them upstops. Six Flags Over Georgia calls them upstops... so to me, they're upstops.

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To echo...the strength isn't in the size of the wheel...remember the entire load has to be carried on the pin that attaches the wheel to the train. Furthermore, remember the whole load is distributed among all the contact points.

On some coasters, you will also notice small steel flanges on either side of the upstop (and on either side of the road wheel!) which will catch the train if the upstop should fail.

Finally, note that on selected coasters, the up-stops are used as road wheels when the train is pulled onto a storage track. Take a look at the storage tracks for Mean Streak, for example.

--Dave Althoff, Jr.

BATWING FAN SFA said:
Didn't Shockwave loose a wheel last season as well? that's probably what led to it's removal for S:UF instead of Whizzer along with protests against Whizzer's removal.

A coaster loosing a wheel isn't exactly a common occurrence, but it does happen (and isn't a very big deal). I seem to remember a hyper coaster (Mamba, maybe?) that lost wheels quite often for a period of time. Also, my dad told me that when he was in Las Vegas, High Roller was closed because a wheel fell off of the train.

Unless a more serious incident was caused by the wheel falling off, I highly doubt that it would be a reason that SFGAm removed Shockwave.