Wheel assembly water misters?

[Hyde]

While riding Millennium Force yesterday, I noticed that they had rigged a hose in the station underneath the flooring to spray mist on the track and wheels as they passed through the station. Sandusky was under a heat advisory yesterday with temperatures up to 107 degrees, which makes it understandable to have this rigging to help keep the wheels from overheating/extra wear.

Has anyone else seen this kind of set up on other roller coasters?

 

[Error]

I305 has them, mostly due to the high amount of friction they produced. It was apparently causing them to deterirate at an alarming rate, making replacing wheel costy.

Sent while out and about

 

[bergochdalbana]

TTD have them to cool the cable, but that's not the same thing, but still is, and Drachen Fire had heaters so that the train wouldn't stall during the ride due to cool bearing/grease.

So there are plenty of these things around so that the trains are able to get back into the station/reduce maintenance.

 

[Youngster Joey]

I believe California Screamin at DCA has them at the launch. I assume to cool down the wheels but I don't know for sure.

 

[Pokemaniac]

Titan at Six Flags Over Texas has them, apparently:

http://coastergallery.com/2001/T31.html

 

[Nic]

I believe California Screamin at DCA has them at the launch. I assume to cool down the wheels but I don't know for sure.

Yes! I knew I'd seen them somewhere. I thought it might've been Superman, but you're right, it was California Screamin'.

 

[Martyn B]

Ahhhhh, this could well be the explanation for my question!

viewtopic.php?f=5&t=34428

 

[Hixee]

I believe California Screamin at DCA has them at the launch. I assume to cool down the wheels but I don't know for sure.

Yes! I knew I'd seen them somewhere. I thought it might've been Superman, but you're right, it was California Screamin'.

Although you'd assume you'd want to cool the wheels down on the brake run, where they're actually hot and need cooling down. Putting misters on the launch would just get the wheels wet and probably not cool them down much at all. I'm willing to bet the misters on California Screamin' are just for effect.

 

[bergochdalbana]

^ Or cooling down the main LIM's between the launches, since the misters are only on between launches.
Could be necessary when it's hot since it's a high capacity ride with many trains.

 

[Hixee]

^Ah, if they're only on between launches that makes sense too.

 

[Nic]

Yeah, pretty sure they're there to cool the LIMs rather than the wheels, as mentioned above. Also, they're more like tiny little fountains rather than misters. Trying to find a pic, but can't find one anywhere.

 

[bergochdalbana]

You can see them operate in the beginning of this video.

[youtube]http://www.youtube.com/watch?v=e_LQRIteFGg[/youtube]

 

[Hixee]

Yeah, they're definitely for cooling the LIMs.

 

[Hyde]

^ You are correct sir, the misters are there to prevent overheating of launch mechanisms/LIMs in the California sunshine.

I did keep a look out on TTD for wheel misters, but didn't find a single one. It would seem that TTD's quick 16 second bursts of speed are not as worrisome as MF's 1 minute ride.

 

[Nic]

Not exactly on topic, but close enough and not worth starting one of its own...

I noticed that X2 has "cooling fins" on its wheels. They're labelled in the diagram on this sign (not that you can really see in the pic)

Best pic I can find is this:

(although, I actually found a very similar pic of the old train which looked like the same/very similar wheels, so they might not be anything new)

Anyway, I can't recall having noticed these before (not that I make a habit of staring at coaster wheels). Is this a very common idea? If not, why would X2 need them? Is it to do with the cars being relatively heavy? A quick google image search suggests that Eejanaika has them too.

Sorry to hijack the topic

 

[Hixee]

It'll probably be due to the fact that X2's trains are heavier. Not only will they allow the wheels to cool faster, but the ribs are an effective way to strengthen the wheel without just making it a solid block. Heavier trains will cause a higher energy build up in the wheels, and I would have thought X2's trains are on the weighty side.

I don't think they're that common though, but I honestly have no idea and there's no way I'm trawling RCDB to find enough examples to confirm this.

 

[andrus]

I305 has them, mostly due to the high amount of friction they produced. It was apparently causing them to deterirate at an alarming rate, making replacing wheel costy.

I305 got them both in the station and at the brakerun. Apparently the ride needs a lot of cooling!

 

[bergochdalbana]

The ridges on the wheels are all about weight savings not cooling. A heavy train will wear out lot's of thing on a coaster, even the track will "wear" out faster due to a heavy train, and even if a wheel is a pretty small part of a coaster, there is loads of them, using X2 as an example and you end up with a total of 140 wheels/train. If the wheels were solid pieces of aluminium they would drastically increase the weight of the trains, but by milling out material so that you end up with notched wheels, you still retain the structural strength of the wheel to levels that are similar to solid wheels, but at a much reduced weight.

Else look at UC...

Also on the water misters on large Intamin coasters, they might as well be there to cool the brakes (magnets/fins) of the trains, since all the kinetic energy of the train is all converted to heat. Large ride such as MF and I305 have the long heavy trains (compared to TTD, KK and Formula Rosso) that enter the brake run at high speed, high speed > high kinetic energy > more heat in the brakes and higher temperature in the magnetic brakes reduces the braking ability (makes them worse). The fins/magnets out in the open are less prone to overheat due to wind/etc. but once in the close confines in the station you might not have the ventilation to cope with the heat build up so they add water misters just like on the LSM launch on California Screaming.
For instance Balder have air-ducts in the floor between the tracks in the station to cool the brakes.

 

[Hyde]

^ Overheating is not a concern for magnetic brakes. Since they offer zero-contact braking for trains, heat is a negligible factor. In order for heat to be a problem, the brake fins would need to get very, VERY hot, to the point that they become malleable and able to warp. This temperature margin is far outside of normal operation. Even then, adding water would be a bad thing, as water would cause rapid cooling which leads to warping.

The misters are there for the wheels, which are no where near as durable as the brakes.

As Nic and UC have been mentioning with wheel design, they offer both cooling and rigidity. This design is found at least on all Intamin and B&M coaster designs.

On a side note, MF still had its station misters going yesterday.

 

[bergochdalbana]

^ If magnetic brakes don't as you say produce heat, why on earth do California Screamin' have water misters on the main launch run, they offer no contact either but still get hot??
60-80% of the energy on an LSM launch moves the train the rest is transformed to heat > electromagnets get really hot.

On magnetic brakes works by inducing eddy currents in the fins, but these currents have nowhere to go so they are transformed into heat, all of it. The only coaster that recovers any form of energy from it's brakes is Freishütz. The rest of the magnetic brakes all transforms all it's energy into heat, contact or not, where else does the energy go it can't vanish into thin air. The faster and heavier the train is the more kinetic energy the brakes have to deal with.
And yes heat do offer changed properties on magnetic brakes. The hotter the brakes are the more the brakes "fade", and once you get to a certain point then you might end up with trains overshooting and causing havoc on the block system forcing the ride to emergency stop. Why else have the people from Intamin talked about that when I was chatting with them at Atmosfear press day and Mack maintenance guys checking the temperatures on the brakes on Blue Fire during it's first year of operation.

Ridges on the wheels are for lightness without sacrificing the rigidity that a solid wheel offer. And the lighter the train the less kinetic energy you have to deal with on the ride.