Jump to content

Roller coaster

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by SupaStarGirl (talk | contribs) at 00:37, 12 January 2007 (rv blanking). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

For other uses, see Roller coaster (disambiguation).
The track of a typical roller coaster. This track scheme is loosely based on the Crystal Beach Cyclone.

The roller coaster (sometimes known as a big dipper in the United Kingdom, or as a jet coaster in Japan) is a popular amusement ride developed for amusement parks and modern theme parks. LaMarcus Adna Thompson patented the first roller coaster on January 20, 1885. In essence a specialised railroad system, a coaster consists of a track that rises and falls in specially designed patterns, sometimes with one or more inversions (the most common being loops) that turn the rider briefly upside down. The track does not necessarily have to be a complete circuit (the antonym of complete circuit is "shuttle"), though some purists insist that it must to be a true coaster. (Not all thrill rides that run on a track are roller coasters). Most coasters have cars for two, four, or six passengers each, in which the passengers sit to travel around the circuit. An entire set of cars hooked together is called a train. Some roller coasters, notably Wild Mouse roller coasters, run with single cars.

There are numerous organizations of people who enjoy roller coasters. Members usually pay a fee to be a part of the club in exchange for discounts and perks, sometimes from the parks themselves.

In what may be the first practical application of the roller coaster, NASA has announced that it will build one to help astronauts escape the Ares I launch pad in an emergency. [1]

Mechanics

The cars on a typical roller coaster are not self-powered. Instead, a standard full-circuit lift-powered coaster is pulled up with a chain or cable along the lift hill to the first peak of the coaster track. Then potential energy becomes kinetic energy as the cars race down the first downward slope. Kinetic energy is converted back into potential energy as the train moves up again to the second peak. This is necessarily lower as some mechanical energy is lost due to friction. Then the train goes down again, and up, and so on.

However, not all coasters run this way. The train may be set into motion by a launch mechanism (flywheel launch, linear induction motors, linear synchronous motors, hydraulic launch, compressed air launch, drive tire, etc). Some coasters move back and forth along the same section of track; these roller coasters are called shuttles because of this motion and usually run the circuit once with riders moving forwards and then backwards through the same course. Some roller coasters are powered by a kind of locomotive. A properly designed roller coaster under good conditions will have enough kinetic, or moving, energy to complete the entire course, at the end of which brakes bring the train to a complete stop and it is pushed into the station. A brake run at the end of the circuit is the most common method of bringing the roller coaster ride to a stop.

One notable exception is a powered coaster. A powered coaster is a roller coaster type ride that instead of being powered by gravity, uses one or more motors in the cars to propel the trains along the course.

File:Roller Coaster-Movie World Australia.jpg
The Road Runner roller coaster at Movie World, Australia

Blocking

Most large roller coasters have the ability to run two or more trains at once. These rides use a block system, which prevents the trains from colliding. In a block system, the track is divided into several sections, or blocks. Only one train at a time is permitted in each block. At the end of each block, there is a section of track where a train can be stopped if necessary (either by preventing dispatch from the station, closing brakes, or stopping a lift). Sensors at the end of each block detect when a train passes so that the computer running the ride is aware of which blocks are occupied. When the computer detects a train about to travel into an already occupied block, it uses whatever method is available to keep it from entering.

The above can cause a cascade effect when multiple trains become stopped at the end of each block. In order to prevent this problem, ride operators follow set procedures regarding when to release a newly-loaded train from the station. One common pattern, used on rides with two trains, is to do the following: hold train #1 (which has just finished the ride) right outside the station, release train #2 (which has loaded while #1 was running), and then allow #1 into the station to unload.


Safety

Because roller coasters are intended to feel risky, accidents such as the September 5, 2003 fatality at the seemingly tame Disneyland Big Thunder Mountain Railroad, attract public attention.

Statistically, roller coasters are very safe. The U.S. Consumer Product Safety Commission estimates that 134 park guests required hospitalization in 2001 and that fatalities related to amusement rides average two per year. According to a study commissioned by Six Flags, 319 million people visited parks in 2001. The study concluded that a visitor has a one in one-and-a-half billion chance of being fatally injured, and that the injury rates for children's wagons, golf, and folding lawn chairs are higher than for amusement rides. [2] In fact, driving to the amusement park has a higher risk of injury than riding the rides at the amusement park. It is not unusual for park management to pay higher insurance premiums for carousels than they do for roller coasters.

Many safety systems are implemented within rollercoaster systems. The key to the mechanical fail safes is the control of the coasters operating computers: programmable logic controllers (often called PLCs). Most rollercoasters run with three separate PLCs; however, only one PLC is required to detect a fault for the ride's fail-safes to be activated. This is often the reason that the ride trains may stop on the lift or the brake runs, yet after a short time the ride starts again without any obvious maintenance by staff. It is likely in such a case that one of the PLCs detected a fault by mistake, and the ride's operator only needed to restart the ride.

Nevertheless, accidents do occur. Regulations vary from one authority to another. Thus in the USA, California requires amusement parks to report any ride-related accident that requires an emergency room visit, while Florida exempts parks whose parent companies employ more than 1000 people from having to report any accidents at all. Rep. Ed Markey of Massachusetts has introduced legislation that would give oversight of rides to the Consumer Product Safety Commission (CPSC).

Many ride accidents are caused by riders or ride operators not following safety directions properly, but in extremely rare cases riders can be injured by mechanical failures. One such example was the 2006 de-railing of one car on the Wild Thing roller coaster at Valleyfair!.

In recent years, controversy has arisen about the safety of the increasingly extreme rides. There have been suggestions that these may be subjecting passengers to translational and rotational accelerations that may be capable of causing brain injuries. In 2003 the Brain Injury Association of America concluded in a report that "There is evidence that roller coaster rides pose a health risk to some people some of the time. Equally evident is that the overwhelming majority of riders will suffer no ill effects." [3]

A similar report in 2005 linked roller coasters and other thrill rides with potentially triggering abnormal heart conditions that could lead to death. [4] Autopsies have shown that recent deaths at various Disney parks, Anheuser-Busch parks, and Six Flags parks were due to previously undetected heart ailments.


See also

Look up roller coaster in Wiktionary, the free dictionary.
Wikimedia Commons has media related to Roller coaster.

References

  1. ^ Chris Bergin (November 3, 2006). "NASA will build Rollercoaster for Ares I escape". NASA Spaceflight.com. Archived from the original on 1 January 2007. Retrieved 2007-01-08.
  2. ^ Levine, Arthur. "White Knuckles Are the Worst of It". themeparks.about.com. Retrieved 2007-01-08.
  3. ^ Blue Ribbon Panel (February 25, 2003). "Blue Ribbon Panel Review of the Correlation between Brain Injury and Roller Coaster Rides - Final Report". Retrieved 2007-01-08. {{cite journal}}: Cite journal requires |journal= (help)
  4. ^ Laino, Charlene (November 16, 2005). "Roller Coasters: Safe for the Heart?". WebMD.com. Retrieved 2007-01-08. {{cite news}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

Template:Link FA Template:Link FA

Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=Roller_coaster&oldid=100117732"