E2 gr14 - Judson STONE. Roller coasters. between innovation and safety LV D. CORCORAN

Transcription

1 ARNAUD Gabriel 20/05/2014 E2 gr14 - Judson STONE Roller coasters between innovation and safety LV D. CORCORAN

2 Introduction: Roller coasters are these famous huge machines, which can be found mainly in amusement parks, generally using advanced technology to make people feel extreme emotions. One can feel new sensations including high speed, loopings, abrupts descents... There are numerous types of coasters; however, even if the shape, the techniques or the materials change from one attraction to an other, safety is always the key-word and the priority. People can experience fear on this type of attraction but should be absolutely never in danger. This is a real challenge for the technical team: people want to experience awesome feelings, but the manufacturer mustn't take any risks with their lives. I) Describing a coaster 1) Some history elements The roller coaster is an old concept, based on Russian mountains which were ice hills located nearby Saint-Petersburg. The first of them appeared in the early 19 th in France, and the first looping section was created in In 1895 in Ohio, the concept of vertical loop came to life, but coasters using it were soon dismantled: it was very dangerous and people suffered whiplash. The very first innovation was the underfriction wheel, which sticks the train to the track. It allowed trains to go faster. In 1902, Leap-the-Dips opened in Lakemont Park, Altoona, Pennsylvania: it is the oldest wooden coaster still operating. Safety lap bars were first used in 1907, way before today harness system. In the US, the Great Depression ended the first golden age of roller coasters, until 1972, when The Racer (a 26m high wooden coaster with a maximum speed of 85 km/h) was built by John Allen: the instant success of this coaster began the second golden age which has continued to this day. In 1959, Disneyland park marked a turn in history: the introduction of tubular steel rails, that can be bent in any direction, allowing many new designs and inversions to be built. Nowadays, most of new coasters include steel track: it's reliable, resistant, and gives a pleasant fluid sensation, but wooden coasters are still being built too.

3 2) How does it work? We will not study old coasters (50 years old or older), because their tracks were not complete circuits. In most cases, the train first leaves the boarding platform, then is grabbed by the chain of the lift hill, and is released at its top to follow the circuit and returns to the station after final breaks. Basic coaster scheme In the early 2000's, new launches began to be built. To give an example, we can consider the catapult launch: the train is grabbed by a hook, such as these for airplane launches. The hook is linked to a huge cable, and when commanded, the cable wraps around a cylinder at the end of the launch section, propelling the train onto the circuit. With this type of launch, train can start the circuit on a flat or a tilted track (e.g. : Space Mountain: Mission 2 (tilted), Kingda Ka (flat) ). The cable winding can be powered by air, liquid (oil or water) or electricity. This technology is used by the army for jet launching on aircraft carriers. The catapult launch is fast, but usually not that comfortable. Some parks decided to implement tires launches: two rows of pneumatic wheels are stuck onto the track, and launch the train by friction. Wheels are made of pneumatic material, to reduce vibrations. A last example of launch (and maybe the most thrilling one) is the LIM-launch: this launch system was developed by Vekoma in 2000, and is based on electromagnetic principles. Series of electric coils (much bigger than these used in electronics) generates a powerful current, creating a magnetic field able to launch an 8-tons train. On every lift there is a anti-rollback system: brakes or rack and pinion system are set onto the track, so that in case of cable failure, the train will remain stuck in position.

4 In 2005, manufacturers started using magnetic breaking: in a traditional coaster, a big central iron blade, set under each car, is grabbed by jaws on the track, and slows down the train to the desired speed. As we can imagine, this system implies quite expensive maintenance. Classic breaking system with jaws Magnetic breaking system With a magnetic brake, trains are slowed by a magnetic field: there is no friction, they are maintenance-free, and braking is really effective! Everyone can experience this system, dropping an iron ball into a metallic cylinder: whatever the speed the ball has at the top of the tube, it will go out slow. 3) Why is it so popular? There are plenty of coasters: iron, wooden, inverted, stand-up, floorless, wings, mini, family, Of course, some cost a lot more than others! The following pictures show a wooden track (a) (first type of coaster ever created), an iron rail with external wheels cars (b) and another with internal wheels car (c). (b) (a) (c)

5 And here are the two types of chassis for iron tracks: Internal fixation External fixation Train have to remain clamped onto the track: engineers had to find a way to create easy-touse switch tracks, in order to send trains backstage. Internal fixation External fixation

6 Coasters can make you feel like you are flying, diving, swimming, running, driving... Sensations are extrapolated, because the body is not familiar with this type of transport. People want to feel great, and know there is no danger. Furthermore, some coasters are themed in relation to their name or layout, which magnyfies sensations due to the circuit and guests imagination. Among the top high thrill elements of past years, we can quote: - the inverted diving loop: on an inverted coaster (track is above the passenger, who has feet in the air), the train goes upside down and goes through a half loop. Oziris (2012 Parc Astérix, Plailly, France) - the zero-g roll: the train does a barrel roll, but the heart of the riders stay on the same line. This is a really strange and appreciated feeling.

7 - the first drop: on almost every roller coaster there is a first big drop. It's the main slope in the circuit, and riders experience a unique sensation of zero gravity. Banshee (2014 Kings Island, Ohio, US) II) Elements of security 1) Technical, software and human elements Those machines have to be perfectly safe, operators have no right to make mistake. After months of research and development, testing on digital models and small physical ones, the track is built, piece by piece. To give an idea, a single piece of iron coaster is 3 to 18 tons weight, and assembly is done manually with a precision of a millimeter. A certification company (TÜV) checks the whole attraction before the tests begin. If everything is alright (the trains don't go too fast, distance between the structure and the riders, harnesses close without difficulty, emergency braking and sensors are ok...), the attraction is tested for the first time. Usually, there are many adjustments to do! After working one or two years on the coaster, it finally opens. The main safety elements are sensors: if a brake is not working, or a harness is not closed, operators must be warned immediately. There are sensors on the track (check the distance between two trains, the train's speed, brakes, scenery elements such as video, track switches), on the train itself (braking elements, harness, sometimes embedded audio) and in the station (access doors, brakes, time between two dispatches). In most cases, a train can leave the station only if two operators push a button at the same time, to double check the whole train: it increases reliability. Checking out the sensors during a test...

8 On Crush Coaster, in Disneyland Paris, cars have weight sensors and trigged rotations depending on the riders weight. Before the first ride, engineers have to verify that every element of the ride is far enough from the cars, so that people can't hurt themselves. In the picture beside, you can see the car template being pushed along the track to ensure every thing is out of reach. In this safety envelope, riders can push their hands up as far as they want, without touching anything. 2) Potential risks Unlike real cars, coaster cars never crash. The rare accidents listed are eventually always due to human mistakes, from the operator or a rider. Lots of messages are displayed all along queuing lines to prevent people suffering from heart, back or neck problems from riding the attraction, even if it looks like a calm one: every person has a different perception of the same ride, and imagination can turn a sensation into a stronger one. A recent accident happened in 2013 in the US: an overweight woman rode a wooden coaster; the lap-bar couldn't totally close, so she was ejected from the train. In 2002, on Rock'n'Roller Coaster in the Walt Disney Studios, a Spanish girl was found inanimated, and died at the hospital a few hours later. The investigation showed she had heart problems, she should not have ridden this 0 to 91 km/h launched coaster. 3) What owners do Once a coaster is delivered, maintenance is the responsibility of the park who ordered it. Every day, technical teams inspect the whole track, inspect the braking systems, the lift, fluid systems (oil, air and water), trains and make all the trains run through the attraction. In rare cases, an external enterprise has to replace some parts of the attraction. On Space Mountain in Disneyland Paris, if the catapult shuts down, it can be fixed only by Dassault Systems technicians. The owner is not permitted to modify an attraction.

9 Conclusion Roller coaster are safe machines, but people still have to responsibly behave while riding. Engineering teams are searching for innovative elements and types of rides, and advanced technologies are constantly being created and adapted to the entertainment world, and people are increasingly enjoying this kind of attraction. The main difficulty is to adapt a system to make people feel extreme sensations, without being dangerous. In this case, limits are not to be exceeded because they're already at their maximum. Sources: