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Exercise 29
Powering the Lift Hill
A lift hill, or chainhill, is often the initial upward section of track on a typical roller coaster that initially transports the roller coaster train to an elevated point. Upon reaching the top, the train is then disengaged from the lift hill and allowed to coast through the rest of the roller coaster's circuit.
Lift hills usually propel the train to the top of the ride via one of two methods: a chain lift involving a long, continuous chain which trains hook on to and are carried to the top; or a drive tire system in which multiple motorized tires push the train upwards.
The Cable lift is a type of lift mechanism that was used on many scenic railway-style coasters, which were built in the early part of the 20th century. Several still exist today and still use the mechanism. This type of lift has returned for Cedar Point's Millennium Force, and will be used for the wooden roller coaster El Toro at Six Flags Great Adventure. The cable lift utilizes a cable loop in place of the traditional chain, which is attached to a short section of chain that engages the train's chain hook. Because a cable is much lighter than a chain, cable lifts are much faster than chain lifts and can be used on much steeper hills - even vertical. A cable also requires far less maintenance than a chain. However, one minor disadvantage of a cable lift system is that it must return to the bottom of the lift hill after lifting each train, which does not apply to a continuously moving chain lift.
Anti-Rollback Device
The familiar "clickity-clack" sound that occurs as roller coaster trains ascend the lift hill is not caused by the chain itself, contrary to popular belief. The cause for this noise is actually a safety device used on lift hills -- the anti-rollback device. The anti-rollback device is a standard safety feature consisting of a continuous section of metal with "teeth-like" protrusions that vaguely resemble a linear gear.
Roller coaster trains are fitted with anti-rollback "dogs" which are essentially heavy-duty pieces of metal which fall and rest in each groove of the anti-rollback device on the track as the trains ascend the lift-hill. This makes the "clicking" sound and essentially allows the train to go upwards only; effectively preventing the train from rolling back down the hill should it ever encounter a power failure or broken chain.
Brake Runs
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.
Brake Style / DescriptionTrim 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.
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.
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.
Brake Type / DescriptionSkid 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.
Fin Brakes / Fin brakes involve a metal fin being attached to the underside 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.
Magnetic Brakes / Magnetic brakes are a relatively new technology that is 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 two rows of very strong Neodymium magnets. When a metal fin passes between the rows of magnets, eddy currents are generated in the fin, which creates a magnetic field opposing the fin's motion.