Rough Coasters

[Adam]

Hey, What do you think determines if a roller coaster is rough? (e.g. sharp turns in the track, bad track connections) I have always thought that sharp turns in a coaster would most likely make that particular coaster rough, but now, looking at new products from Mack (which I presume would be smooth), they have sharp turns to the left the quick to the right, so now I'm not to sure. If someone could help me out that would be appreciated. I have attached two images of Mack coasters (first is a Water Coaster, second is an e-Motion coaster) would these sections of track be classed as "rough"?

[Richard]

There are many different types of roughness. A wooden coaster has a bumpy "out-of-control" roughness that is caused by loosening and degradation of the layers of laminated track as a result of wear and weather. Thunderbolt's chief causes of roughness were bad (terrible) track connections and abrupt transitions coupled with a bad (terrible) restraint design. An Arrow looper's roughness stems from non-parabolic transitions and an inferior train design. Typical roughness would be head banging: where the head hits the restraint. Naturally it is only really a concern on coasters with over-the-shoulder restraints because though rides with lapbars can indeed be rough, its effects aren't felt nearly as much because the waist is significantly less sensitive than the head and it's closer to the track meaning lateral forces and movements are less than at the head. The sharpness of a turn doesn't dictate roughness. A sharp or abrupt turn will lead to higher forces, but so long as lateral changes of force (lateral acceleration) are kept to a minimum, roughness can be kept low. It's all in the transition. Virtually every coaster will have side-to-side movement of the head and body throughout the ride, even sacred B&Ms and Intamins. The key is limiting these to a point where the head doesn't "vibrate" enough to make contact with the restraints. Particularly with older coasters, maintenance can make all the difference. Rides like Corkscrew, Cyclone or Lethal Weapon all can be smooth or rough. It's largely to do with the age of the wheels. As you might know they are steel, coated with a polyurethane (coasters these days use a DuPont composite known as Hylene PPDI), and with time this polyurethane wears down, meaning the wheels are less able to absorb bumps (cause by imperfections in the track or from transitioning). They didn't used to put shock absorption and dampening into the trains like they do these days, as well as spring-loaded guide and upstop wheels so the effects of aging wheels was far greater on these older coasters than it is today.

[Gazza]

Rich is pretty much right. Roughness can be caused by something called "hunting" where the wheel assemblies dont completley line up with the track, so one of the wheels wil be momentairly be out of contact with the track, and if this keeps happening the tiny movments and vibrations translate into roughness. there is no danger to anyone because the other wheels remove the possibility of derailment.

[Nebuchanezzar]

Yah, I thought it had something to do with the wheels bumping the sides of the track (the side wheels) every now and then. And nice explanation Richard.

[Adam]

Thanks guys for your help (especially Richard).

[scott]

May I ask what B&M does to make their coasters so smooth?

[Gazza]

They use Parabolic curves, and a 3D design system so they can ride the ride to see if there are any bumps or oddly shaped curves, so their g forces are perfect with almost no erratic fluctuations. Their trains also have suspension, which makes a difference, and each set of wheel assembiles is complety independently swiveling. Also, i think the wheels on B&M trains are affixed tighter to the track to eliminate hunting, but the trade off with that is that their track panitwork gets worn off quicker.

[Nebuchanezzar]

I heard, off some website whos identity remains a mystery, that the fact that B&M has their side wheels on the outside of the tracks makes for a smoother ride than the widely used wheels on the inside method that many other manufacturers use.

[Adam]

Interesting, because isn't the concept behind Vekoma's new ride system to have the wheels on the inside of the track? I really don't know much about what effect it would have (although having the wheels on the inside looks safer).

[Bussy]

Interesting, because isn't the concept behind Vekoma's new ride system to have the wheels on the inside of the track? I really don't know much about what effect it would have (although having the wheels on the inside looks safer).

I presume you are referring to Neb's post but I am confused because he clearly states that the wheels are on the outside.

I heard, off some website whos identity remains a mystery, that the fact that B&M has their side wheels on the outside of the tracks makes for a smoother ride than the widely used wheels on the inside method that many other manufacturers use.

Personally I think that it makes little difference to that safety factor of a coaster. "The Bus is now leaving for White Stone Outside Dar Stool, Norfolk Island"

[Adam]

Yea, but Vekoma would want to make their new ride system as smooth as possible wouldn't they (i.e. better than their old ride system.)? So if having the wheels on the inside was less smooth, why would they change? I am not saying Neb is wrong, I don't know anything about what effect it has...

[Nebuchanezzar]

Yah, I heard it off some website somewhere, but then, if it doesn't make a difference, why does B&M slap em on the outside anyway? To be different?

[Gazza]

because some manufacturers prefer different ways, vekomas and arrows have their wheels on the insides, B&M intamin and zamperla have them on the outside, it makes no difference because both ways have the potential to be smooth.

[joz]

Exactly, togo wheels are on the outside of the running rails, and no one ever calls a togo ride smooth do they?