Brake run
From Wikipedia, the free encyclopedia
A brake run on a roller coaster is any section of track meant to slow or stop a roller coaster train. Brake runs may be located anywhere along the circuit of a coaster and may be designed to bring the train to a complete halt or to simply adjust the train's speed. Contrary to some belief, the vast majority of roller coasters do not have any form of braking on the train itself, but rather forms of braking that exist on track sections. One notable exception is the scenic railway roller coaster, which relies on an operator to manually control the speed of the train.
On most roller coasters, the brakes are controlled by a computer system, but some older wooden roller coasters have manually operated brakes. These are controlled by large levers operated by the ride operators.
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[edit] Trim brakes
Trim brakes are sections of brakes which are intended to adjust a train's speed during its course rather than bring the train to a complete stop. They may be engineered into a ride at its design stages at certain anticipated troubled spots, or later retrofitted once it's discovered that trains transverse certain areas at higher-than-anticipated speeds. Trim brakes are often either added for safety reasons, to lower G-forces in certain areas, or for maintenance/mechanical reasons, to lower the cost of wear-and-tear caused by the trains traveling at faster than normal speeds.
[edit] Block brakes
Block brakes are sections of brakes located on any roller coaster wherever more than one train is intended to run. They act as virtual barriers between the trains running on the roller coaster, preventing collisions should one train stop along the course for any reason. Because of this, block brakes must be capable of completely stopping the train (should a vehicle preceding the block stop) and starting a train (after it has been stopped). Block brake sections usually start the train again in one of two ways including a slight downward slope to let gravity take its course, or by the use of drive tires pushing the train out of the block.
See Blocking.
[edit] Types of brakes
Various types of braking exist when dealing with roller coasters, some of which have been recently developed due to technological advancements in design.
[edit] Skid brakes
Skid brakes essentially involve a long piece of material, often ceramic-covered, situated in the middle of the track parallel to the rails. When the brake is engaged, the skid raises and friction against the underside of the train causes the train to slow and eventually stop. Skid brakes were one of the first advancements in roller coaster braking and are usually not utilized in modern creations.
[edit] Fin brakes
Fin brakes involve a metal fin being attached to the underside (or the sides) of a train. The track is fitted with two computer-controlled squeezing mechanisms which upon closing, squeeze the fin and either slow or stop the train. Fin brakes are the most common form of brakes on roller coasters today. Sometimes they are thick metal box beams (mostly on Bolliger & Mabillard roller coasters) and are engaged when compressed air flows into a metal drum, pushing joints on two sides in order to close shut two parallel brakes that in turn will drag along the box beam. Fin brakes are designed to be fail-safe, so that a loss of power will cause them to engage.
[edit] Magnetic brakes
Magnetic brakes are a relatively new technology that are beginning to gain popularity due to their high degree of safety. Rather than slowing a train via friction (such as fin or skid brakes), which can often be affected by various elements such as rain, magnetic brakes rely completely on certain magnetic properties and resistance. In fact, magnetic brakes never come in contact with the train.
Magnetic brakes are made up of one or two rows of very strong Neodymium magnets. When a metal fin (usually made of copper and brass) passes between the rows of magnets, eddy currents are generated in the fin, which creates a magnetic field opposing the fin's motion. The resultant braking force is directly proportional to the speed at which the fin is moving through the brake element. This very property, however, is also one of magnetic braking's disadvantages in the eddy force itself can never completely stop a train. This effect of magnetic braking can be explained by an example in which the train's speed is halved as it passes through each set of brakes. The train's speed (in any unit) would initially be 40, then 20, 10, 5, and so on. It is then often necessary to bring the train to a complete stop with an additional set of fin brakes or "kicker wheels" which are simple rubber tires that make contact with the train and effectively park it.
Magnetic brakes can be found in two configurations:
- The brake elements are mounted to the track and the fins are mounted to the underside (or sides) of the train. This configuration looks similar to frictional fin brakes.
- The fins are mounted to the track and the brake elements are mounted to the underside of the train. This configuration can be found on Intamin's Accelerator Coasters (also known as Rocket Coasters) such as Kingda Ka. This configuration is probably less expensive, as far fewer magnets are required.
In terms of pros, magnetic braking is virtually fail-safe because it relies on the basic properties of magnetism and require no electricity. Magnetic brakes are also completely silent and are much smoother than friction brakes; gradually increasing the braking power so that the people on the ride do not experience any unpleasant feelings. Many modern roller coasters, especially those being manufactured by Intamin, have utilized magnetic braking for several years. Another major roller coaster designer implementing these brakes is Bolliger & Mabillard in 2005 on their "Silver Bullet" inverted coaster and in 2006 on "Patriot". These later applications have proven effectively comfortable and relevant for these inverted coasters which often give the sense of flight. There also exist third party companies such as Magnatar tech. which provide various configurations of the technology to be used to replace and retrofit braking systems on existing roller coasters to increase safety, improve rider comfort, and lower maintenance costs and labor.
However, the main disadvantage of magnetic brakes is that they cannot completely stop a train, so they cannot be used as block brakes. They also cannot be conventionally disengaged like other types of brakes. Instead, the fins or magnets must be retracted so that the fins no longer pass between the magnets. These are the most effective brakes that slow the train quickly, and these are failsafe. Accelerator Coasters, for example, have a series of magnetic brake fins located on the launch track. When the train is launched, the brakes are retracted to allow the train to reach its full speed. After the train is launched, the brake fins are raised to safely slow the train down in the event of a rollback
