How Roller Coasters Work

lunch right before this podcast. I'm not feeling so well. Yeah, and everyone else thought, there's probably thinking roly coasters. Uh, So we decided we wanted to talk about how roller coasters work. Um now, now, Chris, uh, are you a roller coaster fan? Yeah? Is that a lie? No, it's not a lot checking But but I'm not an extreme roller coaster fan. I'm not the kind of person that travels across country or sometimes around the world to find

the biggest and fastest and most terrifying roller coaster. I'm I'm generally quite happy with the stuff down at the local amusement park, and honestly, I'm a fan of the wooden roller coaster. Yeah, those are. If they're well maintained, they're great, and if they're not, they will beat you up. I d like it when they beat you up there. Yeah, gosh, Okay, Well I've got a coaster for you to ride. Um. I am also a fan of roller coasters. I would not call myself a die hard fan because I have

Also I've only taken trips to like Cedar Point. I'm just gonna say, but that's a good place to go. Yeah, it's across the country from where we are. I haven't I haven't specifically gone to things like King's Island or anything like that to ride all of the roller coasters out there. But I do love roller coasters, and I love the really super mega coasters too, the really really tall ones love them. So we thought we'd talked a

little bit about what makes roller coasters work. Yes, and uh, maybe we should give a little history of the roller coaster first. And this is uh, if you've already seen the the episode that High Speed Stuff did. Uh, they took a little bit different tech on the roller coaster than we're going to I think. Yeah, they talked most They talked mostly about the tallest and the fastest and

that kind of thing. Yeah, definitely good check out. Yeah, we're gonna talk more about the actual mechanics behind roller coasters, so, uh, you know, if you want to know about the fastest and tallest ones, definitely check out the High Speed Stuff episode. It's archived, so the history of roller coasters. So we're

gonna go to France for this. Yeah. Actually, if you want to go even further back, the genesis of the whole idea of the roller coaster just comes from the fact that human beings we as a whole, are insane, and occasionally we like to throw ourselves down inclines and see how fast we can go before we come to a stop, whether that's sudden or hopefully a nice, gradual, gentle stop. Yeah. You know, I was thinking that very thing when I was watching the ski jumpers at the Olympics. Yeah,

not too long ago. What made somebody decide to you know, hey, I wonder how far I can go? Right, this is a really tall, tall mountain. I want to strap some wood to my feet, slide down at a blistering speed

and then jump off something. Yeah, that would, I would say, be the same sort of the the thrill seeking part within US that generated roller coasters France that kind of took an idea that had already seen some uh some success in Russia, which was essentially a series of slides that would go down mountains that were you know, those slides were covered in snow or ice and people would slide down them. Um. So that's the you know, the

roller coasters based off of just a slide. Now, the roller coaster in France that you're thinking about, I believe is a that was the first one that was a documented case of a cart on a track. Yes, and that was which was an attempt to uh to actually take the Russians idea and make it something that you could do all the time because Russians, as it turns out, in in France, snow is not always on the ground. So if you don't have snow, you don't have something to uh to make that trip down the hill at

least a little pleasant. Then you have to build tracks and have a cart with wheels on that track so it goes down the predefined Um tut well, I was going to use a word other than the track, but on that track. And the first American coaster was a it was a converted coal train. Yes, it was not the saxophone player. No, no. So this this coal train would go up a really nice picturesque mountain in Pennsylvania and then um, once it got to the top, while it was only one way to go back, and that

was back the way you came. So they would just essentially kind of a roll backwards, screaming all the way down as people held on for dear life. And I'm sure it was very bumpy and chaotic ride. And I would go on at five times so that I'm sure, however, that it had not been inspected every day like modern day roller coasters. Yeah, I definitely would have. I would have been taking my life into my own hands, especially

after ride number one. Uh So this leads us to the Wooden roller coaster, which is kind of the basis of all coasters that followed. And the Wooden coaster is a is a thing of beauty. I'd say, you know, the famous one in Atlanta is the Great American Screen Machine. Yes, yes, my my favorite would be uh thunder Road at Paramounts Caro Wins near Charlotte, which is where I grew up. I have not written that one, so let's bumps and and and jolts on that one, right, Yeah, well then

the wooden ones, dude, tend to build that up. So it's based on the principle of gravity pull stuff down. Yeah. Well there's some other stuff in there too. Yeah, but basically gravity is one inertia shore cy triptal force if you want to get technical. But blah blah blah blah.

So the basis of our roller coaster is that some sort of mechanism pulls you up to the top of a very tall hill and then the and you must raise your hands in the air as this is happening, apparently, I mean you have to do it, all right, We're gonna get mailed about that, and you get the answer it so aren't you supposed to raise your hand? And I always wondered that, Okay, it's gonna take a good seven minutes to get to the top of this hill.

Why is everybody raising their hands? Now, well, it's people who are nervous. I assume at any rate, the once you get to the top of the hill and you start going down, then gravity pretty much does the rest of the work for you, and you are pulled along the track. You might depending on the older coaster have a second hill that will there will be some sort of mechanism to pull you up the second hills that you've finished the rest of the trip, or if the

first hill is tall enough, that might be it. That might be the enough to generate the h the the energy you need to complete the entire ride. Now, in the case of most wooden roller coasters, this energy is generated through a chain lift, which it's just the sound of the that's part of it. Yeah, that's part of it. There's there's actually a second element that also can make

that ratcheting noise. But uh, the way a chain lift works is that along the first hill there is a length of chain that's and sort of a conveyor belt configuration, and it's being turned by a very large engine and and some wheels. So the underneath the coaster train itself are a series of hinged hooks and uh, the the term for this is chain dogs. So the chain dogs

hook into the chain the loop of chain. The chain as it turns or as it is propelled up the hill through the turning gear, pulls the coaster up to the top. And as the coaster gets toward the top, the hinged hooks unhooked from the chain, and uh, the coaster is pushed over the very top of the hill and it goes down and then gravity does the rest. Right. So it's a very simple mechanism really when you look at it, I mean, there's there's not a whole lot

to it beyond that. Um, as far as getting the train started, now, stopping the train is a different matter. Well not entirely in a way, because you're moving basically. For those of you who have taken physics yet, I know some of you probably haven't yet because we have some younger listeners. Um, going up the hill, you've got lots and lots of potential energy, energy that's being built up or or just waiting to be released, I should say.

And as soon as you get to the top of the hill and it the train starts to go over the hill, it's it changes into kinetic energy, which is you know, who look out, we're moving, but very good stopping. I think that's actually in most textbooks, who look out we're moving? It Well, it wasn't mine, although I have to admit it was written in blue ink next to the text, so maybe it wasn't put there by the publisher. But that said, getting to the to the end of

the line. Um, you know, by by putting hills in strategic places, you can use those to slow the train down by converting that kinetic energy back into potential energy, right and through things like friction, that's always going to take away some of your energy. You lose energy in the form of heat, so the coaster will generate he does it's moving around, and that that also means that

you have a net loss of of energy. So your your coaster is going to slow down over the course of the track, unless, of course, you were to somehow maneuver it so that it hit a infinite hill going downward. But um, no one's figured out how to do that yet, or else I would have written it already. Actually you'd still be on it. Yes, technically I would still be writing it. I'm calling you from the infinite roller coaster

and so anyway, um, so yeah, you've got Now. Now here's a couple of things for us to talk about. The breaking system. I mean, there is usually a breaking system at the end of the track, because other ways you just have to wait for its a coast to an end. Um. But I imagine that would be far less effective if you didn't use other methods to slow

the train down enough to let the breaking system. Sure, but you know most coasters have been on there's a there's a very audible and physical breaking moment where you you're actually thrown forward a little bit from the coaster coming to a stop. Is that that explains the permanent indentation I have across my forehead from from the seat in front of you. Um. So, the the coaster has these fins that go down below the the coaster to swim.

The fins are used as part of the breaking mechanism. Now, there are a couple of different ways you can use the breaking mechanism. You could have one that just uses physical friction. So the the brakes are all built into the track, not into the train. So the right Yeah, so the track has this this breaking section along part of it. As the train passes through the brakes, UH initiate and then close in on the fins and then

slow or and slow the train and then stop it. Um. But it doesn't have to necessarily just be physical like that. You can also use magnets. You could have a you can have fins on the coaster that have a metal that reacts to magnets, and then you use very powerful magnets which will gradually slow and and then stop the train from moving, sort of the the opposite of a magleev train, Not literally an opposite, but the magnets to stop.

There are coasters actually use magnets to to push a train, but there there aren't a whole lot of coasters like that, but we'll talk about those in a second. So, um, the other thing you have to remember is that there are, uh, there are other wheels on the coaster itself that helped prevent it from flying off the track. Yes, so you usually have a set of wheels. First of all, there's

the set that's on the track itself. There's usually a set that's on either side of the track to keep it from slinging off to the left or right, and then there's a set underneath the track to keep it from flying off when you go uphills. That would be sort of a buzz kill. Yeah, there's nothing quite like having your coaster corene off the roller coaster track to really ruin your time at the fair. Yes, that would that would need to do that. As a friend of

mine once said, I will ruin your whole day. So that's the traditional coaster chain lift. That's what you see on wooden coasters most of the time. And wooden coasters have a lot of limitations because they need, you know, you need to build that that really strong support to

keep the coaster stable. That's where you see all that lattice work, where all the cross beams that are supporting each other, which is why most wooden coasters don't have things like inversions and version of course, will be any time where the coaster is turned upside down. Um, you

don't see many of those in wooden coasters. I've heard there have been a couple that have done it, but it's it's not easy to do just from the the standpoint of you have to be able to support the track also, of course, would is something that ages with the the environment. You've got a lot of you know, heating and cooling, expands and contracts the wood plus you know,

rain and other things termites. I mean, these are things that you have to be wary of because when you're building the infrastructure for a roller coaster, obviously you want to keep it safe, so you're uh, you know, no one gets hurt, so it requires quite a bit of maintenance. Yeah, that's that's why most coasters, wooden coasters take a formation of what I always heard as an out and back. It goes out through the park and then comes back to where started. Um, there aren't. It's the thrills of

the ride are all based upon the hills. You know, how high you go up on that first hill, how fast you're going when you hit the bottom. Yeah, the angle of the drop so that it you know, makes your stomach feel like it's dropping out right, right, So those would be where all the thrills are come from from those, But then came tubular steel coasters. Now these are the monsters that let you do things like inversions, cork screws, em molment's, uh loops, that kind of stuff.

And uh, these are the coasters I love. Yeah. Well, uh, the steel being you know, certainly more weather resistant um than the wood, and uh, of course it can be made into all kinds of shapes, um, so you can you can do all kinds of things. And it also allows you to do in addition to uh, you know, things simple the bends and things, you can also do different kinds of you make different kinds of cars, like the stand up and sit uh. You know, the inverted

and suspended cars right where the track is above you. Yeah. Yeah, the ones that make you feel like you're flying through the air. Yeah. But you can't do that with a wooden coaster, because you have to you can. You can do all these things with the track and subsequently build the cars to take advantage of that. Right, so you can also put in new forms of launching your coaster. So some some tubular coasters still use the the chain lift method, which is, you know, the same way they

all the wooden ones do. Well, it works, but a lot of them also use, or rather instead will use something like a catapult launch, yes, which, as you would imagine it, it is, uses a device to launch the train very quickly from a standing position to full speed. Um. And there are various ways of doing that. Some of them use linear induction motors uh. And that's where you generate an electromagnetic field to uh to move the coaster

along the track. Now, there aren't very many of these there only I think maybe half a dozen to a dozen or something like that, just because it's i mean, that's a very technical way of doing it, and there are other ways that are not as technical as people have found to be easier, so you don't see those uh that often. But another method just uses a series of wheels on either side of the coaster. Yeah. Can I tell you a story? Go ahead. So the very first time I got on the Hulk ride UM down

in Orlando, Florida. UM, I we my wife and I were sitting in the car and looking up the hill and we saw, you know, of course we're at that point, we were on a chain lift, so because they were sort of man, you know, doing that to do the bulk lifting, if you will, to get us started up

the hill. So we're looking up and I see all these wheels spinning on either side of the track, and suddenly my mind flashes back to this hot wheels set of my brothers, which had a little rubber wheel on either side of the track, and I said, oh, yeah, that's the the wheel they use to you know, propel the cars around the hold on. That was about the point.

That was about the point at which we caught those wheels, and the wheels spin in opposite directions of from one another, and just the car takes off exactly the same principle that you see and things like like automatic baseball pitching machines where it's just it's using that amazing amount of friction to propel you forward. And uh so that's that's what it works. Yeah, it does work. And then there are hydraulic and pneumatic launch systems. Now, hydraulic launch systems

these are pretty cool. They use the hydraulic hydraulic pumps which pump fluid into a piston. Right, So you've got one side of the piston, the wet side, which is where the hydraulic fluid is pumped in, and you have the dry side, which has gas in it. Alright, So as you're pumping fluid in, it's pushing the piston towards the the gas end, which is compressing the gas, and

you create and credible amount of compression. Yes, Now, when you've built up that compression to a certain amount, you are able to release that compression, which then uh generates enough energy to move some a winch very very very quickly. Now, the winch pulls a line which is attached to the the the base of the coaster itself forward. So the

winch is turning really really fast. It's pulling a line kind of like if you were reeling in a fish, right, but reeling in a fish faster than any human being could ever reel a fish in. This pulls the coaster forward and launches it from the standing still to oh my god, I can't believe how fast we're going. Yes, they've been on several of these. Then there's also the pneumatic one, which uses air compressed air to launch vehicles. It's kind of similar in a way, although it doesn't

you know, there's no there's no hydraulic fluid there. There aren't very many pneumatic launch coasters. Most of the catapult ones that you, okay, uh find in amusement parks today are of the hydraulic launch variety or use the wheels on either side the friction method. Uh So, I was gonna talk a little bit about a very specific um launch coaster just because it's a good example, the top thrilled Dragster at Cedar Point. Okay, this coaster is a

very simple coaster in a way. Uh. It has a straight track from the launch point that then shoots straight up four d and twenty feet. You turn ninety degrees and you come back down that that hill and then you come to a stop so uh at launch when you when by the time you are starting to go up that hill, the coaster is going approximately a hundred

and twenty miles per hour UM. It's pretty fast. What's really interesting is that there are computer systems that judge, based upon the weight of the train, how much energy is going to be needed to to propel the train up and over the hill. Now, ideally you're going to use just enough energy for that to barely happen, right, because you don't want to use too much. You don't want to propel them too quickly or else they're gonna

be coming down that hill faster than they are supposed to. However, if you don't use enough, well, then you start to slide backwards. So sometimes it does happen. I actually saw that I've written this this coaster. I'm sure several of our listeners have also written it UM and I have seen while waiting in line a coaster come back down the hill. It's not as scary as you would think.

There are permanent magnets in the track that activate after the train goes by that slow the descent, so it's not like it's not like you're hurtling down a hundred twenty months per hour. They had to have been prepared for such an eventuality if they were, you know, concerned enough to put in a system that would automatically detect. So the magnets are are what save you in that sense.

And their permanent magnets are not electro magnets because of course they were like tromagnets and there was an electricity failure, you wouldn't have the electricity to generate the magnetic field. So with permanent magnets, they're all there's always a magnetic field involved. They don't have to worry about, you know, the somehow losing the ability to generate the electromagnetic field. Um. It's a great coaster, by the way, especially if you can ride in the very front car. I'll take your

word for it. I wrote it twice. Um, not my favorite coaster, but it is a pretty good one. Um. Let's see that pretty much covers the basis the basics of roller coasters. Uh. I mean, as you mentioned, there are those that are suspended coasters where the track is above you, but they work pretty much on the same principles as the ones where you're you're on top of

the track. That's the beauty of roller coasters is that while you can put in new tricks and twists and things like that, the the basis for the entire ride is still grounded in physics. Pretty neat it is. Indeed. Um, you know, you can get very technical and talk about inertia and all that stuff from the science lab. I will thank you to keep your science out of my tech stuff, just like I just like the fact that we have another podcast where I can I can conveniently

so uh. And I was also going to mention, uh. Suspended coasters also have a pivoted joint. Many of them have a pivoted joint so that when you go yeah, so that when you go around turns, you swing out. Like we're doing this stuff. It's too bad this isn't a video podcast. But yeah, when you go around, when you go around curves, because it's a pivoted joint, you swing out due to centripetal force and that that also those can be a lot of fun. Not all of

them have the pivoted joints. Some of them are more or less locked into place. Um. Now we also can talk a little bit. There are most of these these modern roller coasters have very sophisticated computer systems in them, which have sensors along the track that can tell the master computer system where each train is, how fast it's going, and uh, if there's a problem, can activate the various braking systems along the tracks so that there are no collisions.

So when everything's working fine, Uh, if something were to happen, like let's say that a train stalled out for some reason, maybe the chain lift uh stopped, or maybe a train for some reason did not make a hill that it was supposed to. Um, the operator can shut down the ride. Some cases it's all automated and the operator has even taken out of the equation. Uh. But these are just pretty basic sensors, really proximity sensors. They're usually very sensitive.

But it's not like there are anything special, you know, that's unique to the roller coaster industry. UM. And of course, uh, you know, the state regulators and I'm pretty sure every state are required to go out and check these. Motion pretty much takes care of that. Yeah, yeah, well it depends on the I don't think OSHA actually does the

roller coaster inspections, do they? Well, they definitely come in if there's ever any problems Okay, because that was under the impression that in most cases is the state that's responsible for that. But I am well, I know that I know that whenever there's a I know that whenever there's an incident making air quotes that that OSHA does come in and does an investigation. So if nothing else, you do the the you know, administrative work so that you don't ever have to endure that because it only

is a legal nightmare, it's a pr nightmare. And plus, I mean, people just no one wants anyone to get hurt while they're operating stuff for boxers, UFC fighters. Okay, some people do, but not in roller coasters, right, And of course uh and of course, um, you know, make sure that when you're interested in writing one of these machines that you follow the instructions because you know, people of a certain height, people of a um you know, if you have and medical conditions, you shouldn't be writing

these things because especial forces can be a lot. Yeah, and and the safety equipment on these things is designed for for a pretty wide range of people. But if you fall outside that range of people, you definitely shouldn't be on the coaster because there's no guarantee that safety equipment is going to work for you. Yes, and so um yeah, as as some like when I was very little, I know that I wasn't allowed to go on a certain roller coaster because I didn't quite make the height requirement.

When I was bigger and I got the ride that I saw why because I had the shoulder harness thing and it would have gone right over my face, Like my face would have been partially blocked by the shoulder harness coming down because it was one of the the U shaped ones and that would not have been a very comfortable ride. So it was fault for the best.

So what's your favorite roller coaster of all time? Um, keeping in mind that, uh, you know, I'm not into the super duper preaky cool coasters like you like the kiddie coasters already established that, Um, just going by by my personal favorite, like by how much I enjoyed it. I think the dueling dragons down at Universal Studios. That's not kidding coaster. Well, no, it's not good. It's not like you know, it's not like the you know, I

like both of them. I like the fact that that they can make it feel like that's one of the cool things about coasters is they they like putting you in these tunnels where you feel like you're gonna lose your head, even though it's way there's no way you could ever do that. And when you're when they raise the Fire and Ice Dragon coasters, you feel like you're gonna touch You see the feet of the people on the ride and it looks like you're gonna, you know,

smack into them. My favorite is whichever side ends up going up a wall at one point, and I can't remember which side. Didn't remember now it's been ten years, it's been a while since ever. My favorite is the Millennium Force at Cedar Point. Yeah, fantastic roller coaster, and it's mainly for the first drop, which is really really intense. Goliath over at six Flags is pretty good to it.

If you can't ride the Millennium Force and you're in Atlanta, go ride Goliath over six Flags because it's not I'm not gonna say it's equivalent because I'm letting them force. I think it's still a superior coaster, but it's it's a good coaster, especially if you you know, you're like me and you don't mind the mind numbing drops if enjoy those, That explains why never mind. Well, I guess that wraps it up for roller coasters. Why don't we

go on to a little listener mail. This listener mail comes from George, and George says, Hey, I have an iPhone three G and I'm wondering which is safer three G or G p r S because I'm always hearing that phone signals cause radiation. But I kind of believe this, So could you please tell me which is safer or gives out less radiation? Thanks? Love the podcast. Well, George, I hate to break this to you, but cell phones

work on radiation. It's all the frequencies that are coming in and out of your cell phone that that's energy that is radiating from your phone going to your phone. All cell phones give out radiation apparently, or when you talk then when you listen. I found out the other day. Now, radiation does not necessarily mean that it's harmful. Radiation is just that's energy moving out. That's it doesn't necessarily mean

it's harmful energy. Now, as far as cell phones go, these studies are inconclusive right now as to whether or not cell phone use Extended cell phone use causes any kind of physiological effect, like whether it would be uh a cancer or if it would uh negatively affect your brain functions. There's just not enough information there for anyone

to really say for sure. The information we do have so far suggests that if there are any harmful effects, it's gonna have to come after years and years of use, because there's just not a lot of documented cases of it out there. I wouldn't worry about it too much.

And really, when it comes down between three G and gprs not a whole difference, because you're just talking about two different frequency bands, and most of of the information and I've seen suggests that depends more on the cell phone than it does the frequency on which it is broadcasting. Some cell phones are gonna be powerhouses, and some cell phones are not gonna be able to transmit through cardboard.

Although the location of the antenna apparently does make a difference to some cellphones have the antenna farther away from your head, some closer. Um, I'm sure that the people who are most worried about it will tell you that it doesn't matter. It's all radiation and it's right next to your head. Um. So well, George I guess what we're saying is that keep looking for studies about it, because no one's really uh definitively come down and said whether or not they cause any harm in the future. UM.

I'm I'm still using my three G cell phone. I'm not too worried about it. Uh. So you know, keep an eye out. You've got an iPhone. There's probably an app for that. Um and uh if we hear anything else will up to it, will probably do an episode about it. So if any of you have any questions, concerns, criticisms, you want to tell us what your favorite roller coaster is, you can write us. Our address is tech stuff at

how stuff works dot com. Remember we have a live show every Tuesday at one pm Eastern and you can find that at our blogs blogs dot how stuff works dot com. And Chris and I will talk to you again really soon. Come on, let's go, let's go, right, Okay for moral on this and thousands of other topics, is a how stuff works dot com and be sure to check out the new tech stuff blog now on the how Stuff Works homepage. Brought to you by the reinvented two thousand twelve camera. It's ready, are you