A roller coaster is an amusement park ride where passengers sit in a series of wheeled cars that are linked together. The cars move along a pair of rails supported by a wood or steel structure. In operation, the cars are carried up a steep incline by a linked chain. When the cars reach the top of the incline, they roll free of the chain and are propelled downward by gravity through a series of drops, rises, and turns. Finally the cars are braked to a stop at the starting point, where the passengers get out and new passengers get on. Roller coasters are considered by many to be the most exciting ride in any amusement park.
The origins of the roller coaster probably date back to Russia in the 1400s, where ice sledding was a popular winter activity. It became so popular that people in relatively flat areas constructed their own hills out of snow and ice. The tops of these artificial hills were reached by way of elevated wood towers with stairways from the ground. For a small charge, people could climb the stairway and take a quick, exciting ride down the hill on a sled.
By the 1700s, many owners of ice hills found a way to extend the profit potential of the ride beyond the winter months. They mounted wheels under small sleds and replaced the ice hills with ones constructed of wood. Brightly colored lanterns were hung along the slope to allow night operation.
Visitors from France saw these rides, which they called the Russian Mountains, and took the idea back with them. The first wheeled coaster opened in Paris in 1804, and the coaster craze quickly spread throughout France. As the popularity of the rides grew, operators vied for the public's patronage by building faster and more exciting coasters. Unfortunately, safety devices did not keep pace with the speed, and accidents were common. By the mid-1800s, the increasing number of injuries and a general loss of public interest took their toll. One-by-one the Russian Mountain coasters were dismantled.
The development of the roller coaster might have stopped there had it not been for a defunct coal-hauling railroad in the United States. The Mauch Chunk inclined railroad was built in Pennsylvania in the early 1800s to haul coal from a mine atop a mountain to barges in a canal below. Mules hauled the empty cars up the hill, and gravity brought the loaded cars, along with the mules, back down. In 1874 mining operations changed, and the railroad began hauling sightseers instead of coal. The one-and-a-half hour round trip cost one dollar and was an immediate success. The railroad continued to carry passengers until it closed in 1938.
The success of the Mauch Chunk inclined railroad as a tourist attraction provided the inspiration for several similar amusement park rides on a smaller scale. In the United States, LaMarcus Thompson built his Gravity Pleasure Switchback Railway ride at the beach on Coney Island, New York, in 1884. For a nickel, riders rode cars that coasted from one elevated station to another over a series of gentle hills supported on a wooden trestle. At the opposite end, the cars were switched onto a parallel track for the return trip.
The second roller coaster on Coney Island was built in late 1884 when Charles Alcoke opened his Serpentine Railway. Alcoke's coaster was the first to use an oval-track design. Riders sat sideways on open benches as they were whisked along at what was then considered to be a break-neck speed of 12 mph (19 kph). A third coaster was built on Coney Island in 1885 by Phillip Hinkle. Hinkle's coaster incorporated a chain lift to carry the cars up the first hill, thus allowing the passengers to board at ground level and saving them a climb.
Roller coaster development hit its peak in the 1920s when there were more than 1,500 wooden coasters in operation in the United States. The economic hardships of the 1930s and the wartime material shortages of the 1940s put an end to that era. Amusement parks closed by the hundreds, and their wooden roller coasters either fell into disrepair or were tom down. It wasn't until Walt Disney opened the Matterhom Bobsled ride at Disneyland in 1959 that the era of modern steel roller coaster design began. Ironically, it took the construction of a new wooden coaster—the massive Racer at Kings Island near Cincinnati, Ohio, in 1972—before the coaster craze really caught on again.
By the late 1990s it was estimated there were over 200 major roller coasters in operation in the United States, with more being added every year. In May of 2000, the Millenium Force opened at Cedar Point in Sandusky, Ohio. At 310 ft (94 m) tall and going 92 mph (148 kmp), it is the tallest and fastest roller coaster in the world.
Roller coasters are generally classified as either wooden coasters or steel coasters depending on the materials used for the support structure.
Wooden coasters use massive wooden trestle-style structures to support the track above the ground. The wood is generally a construction grade such as Douglas fir or southern yellow pine and is painted or otherwise treated to prevent deterioration. The wooden components are supported on concrete foundations and are joined with bolts and nails. Steel plates are used to reinforce critical joints. As an example of the immense number of parts required to build a wooden coaster, the American Eagle built for Six Flags Great America in Gumee, Illinois, used 2,000 concrete foundations; 1.6 million ft (487,680 m) of wood; 60,720 bolts; and 30,600 lb (13,910 kg) of nails. It was coated with 9,000 gal (34,065 L) of paint.
Steel coasters may use thin, trestle-style structures to support the track, or they may use thick tubular supports. The track is usually formed in sections from a pair of welded round steel tubes held in position by steel stanchions attached to rectangular box girder or thick round tubular track supports. All exposed steel surfaces are painted. Steel coasters can be just as complex as wooden ones. For example, the Pepsi Max Big One coaster at Blackpool Pleasure Beach in Blackpool, England, used 1,270 piles driven into the sandy soil for the foundation; 2,215 tons (2,010 metric tons) of steel, and 60,000 bolts. There were 42,000 sq. yd (35,087 sq. m) of painted surfaces.
The track and lift chain on both wooden and steel coasters are made of steel, and the cars usually have steel axles and substructures. The car bodies may be formed from aluminum or fiberglass, and the car wheels may be cast from urethane or some other long-wearing, quiet-running material.
The design of a roller coaster ride is the first and most important part of the manufacturing process. Because each roller coaster is unique, every detail must be designed literally from the ground up.
To begin, roller coaster designers must consider what kind of riders will use the coaster. If the coaster is designed for small children, the hills and curves will be gentle, and the cars' speed will be relatively slow. Families usually want a somewhat faster ride with plenty of turns and moderate forces. Ultimate thrill seekers want extreme heights and speeds.
Designers must then consider the space available for the coaster. Roller coasters not only take a lot of ground space, but also a lot of air space. Designers look at the general terrain, other surrounding rides, power lines, access roads, lakes, trees, and other obstacles. Some amusement parks have added so many rides that a new roller coaster has to be designed to thread its way through existing rides and walkways.
The next objective for the designers is to achieve a unique "feel" for the coaster. Designers can draw on a number of techniques to provide a memorable ride. The initial incline can be made steeper or the speed of the lift chain can be made slower to heighten the apprehension of the passengers. Once up the incline, the first drop is usually designed to be the steepest, and therefore the fastest and scariest. Other drops can be designed with a brief flattened section in the middle, and are called double dips. Drops with very abrupt transitions to a flat or upturned section are called slammers because they slam the passengers down into their seats. Letting the cars run close to the ground, in what is called a gully coaster, gives the illusion of increased speed.
The advent of steel construction for coasters has allowed a number of variations on the basic roller coaster ride. In some modern coasters, the passengers sit suspended below the tracks rather than riding on top of them. In others, the passengers ride standing up rather than sitting down. Some coasters, known as bobsleds, have no track at all, and the cars roll free in a trough, like a bobsled run.
Most of the actual design and layout of a roller coaster is done on a computer. The height of the first incline must be calculated to give the cars enough energy to propel them all the way through the ride and back to the station. The horizontal and vertical forces that the loaded cars exert on the track must be calculated at every point to ensure that the support structure is adequate. Likewise, the forces exerted on the passengers must be calculated at every point. These forces are usually expressed as "g's," which are multiples of the force that gravity exerts on our bodies. For example, if a person weighs 100 lb (45.5 kg), then a 2 g force would exert 200 lb (91 kg) of force on that person. Coasters in the United States generally exert no more than about 3.5 g's, which is the limit that most people find tolerable. Three coasters outside the United States exert more than 6.5 g's and are considered ultra-extreme. Jet fighter pilots black out at about 10 g's.
Because each coaster usually incorporates one or more new and untried features, a working prototype of the new features may be built for testing and evaluation. The prototype is erected at the manufacturer's facility, and weighted test cars outfitted with instrumentation are propelled through the test section at the desired speed. Based on these tests, the designers may alter their original design before building the final product.
When the calculations, design, and testing are complete, a computer-aided drafting (CAD) program is used to prepare detailed drawings for each of the thousands of parts that will be used to build the new coaster.
The Manufacturing Process
The actual physical construction of a roller coaster may take place in a factory or on the amusement park site depending on the type and size of the coaster. Most steel coasters are built in sections in a factory, then trucked to the site and erected. Most wooden coasters are built piece-by-piece on the site. Here is the typical sequence of operations for manufacturing both modern steel coasters and classic wooden coasters.
Preparing the site
- 1 Before the roller coaster can be installed, the area where it is to be located needs to be cleared and prepared. This is usually done in the off season when the amusement park is closed. If it must be done while the park is still open, the area is fenced off to prevent the public from wandering onto the construction site.
- 2 If there are existing structures, vegetation, or utilities that need to be moved or demolished, this work is done first. If any of the surrounding terrain needs to be filled or excavated, that work is also done at this time.
- 3 Holes for the support structure foundations are surveyed and drilled or dug. Sturdy wooden forms are constructed to hold the concrete for each foundation point. In some areas where the soil is very sandy, large wooden piles may be driven into the ground as foundations rather than using poured concrete. If concrete is used, it is brought to the site in mixer trucks and pumped into place by a concrete pump with a long, articulating arm that can reach each foundation form. Connector plates are imbedded into the concrete on top of each foundation to allow attachment of the supports.
Erecting the main support structure
- 4 When the foundation is in place, work begins on the main support structure. The supports for steel coasters—in fact, almost all the parts for steel coasters—are made in a factory and shipped to the job site in sections on trucks. In the factory, the pieces for each support are cut and welded into the required shape using fixtures to hold them in the proper orientation to each other. If a complex three-dimensional bend is required, this may be done in a hydraulic tube bender that is controlled by information from the computer. On wooden coasters, the material for the supports is usually shipped to the site as unfinished lumber and the individual pieces are cut and assembled on site. In either case, the lower portions of the main supports are lifted by a crane and are attached to the connector plates protruding from the foundation points.
- 5 Once the lower supports are in place, they may be temporarily braced while the upper sections are lifted into place and connected. This work continues until the main support structure is complete.
Installing the track
- 6 With the main support structure in place, the track is installed. On steel coasters, sections of track are fabricated in the factory with the stanchions and tubular tracks welded to the track supports. After the sections are brought to the site, they are lifted into place, and the track ends are slid together. The sections are then bolted to the main support structure and to each other. On wooden coasters, wood tie beams are installed across the top of the main support structure along the entire length of the ride. Six to eight layers of flat wood boards are installed lengthways on top of the tie beams in two rows to form a laminated base for the rails. The rails themselves are formed from long, flat strips of steel screwed into the wood base.
- 7 On steel coasters, walkways and handrails are welded in place along the outside of the track to allow maintenance access and emergency evacuation of passengers. On wooden coasters, the portions of the tie beams outside of the track are used as walkways, and handrails are installed.
- 8 The lift chain and anti-rollback mechanisms are installed on the lift hill, and the braking device is installed on the final approach to the station.
Fabricating the cars
- 9 The individual cars for the coaster are fabricated in the factory. The subframe pieces are cut and welded. The bodies are stamped from aluminum or molded in fiberglass, then fastened to the subframe. Seat cushions may be cut from foam, mounted on a base, and covered with an upholstery. Running wheels and guide wheels are bolted in place with locking fasteners. Brake fins, anti-rollback dogs, and other safety components are installed.
Finishing the ride
- 10 When the main construction is completed, electrical wiring is installed for the lighting, and the entire ride may be painted. The boarding station is constructed, signs are installed, and the landscaping is put in place.
The design and construction of roller coasters are covered by numerous governmental safety regulations. The materials used must meet certain strength requirements, and the actual construction is subject to periodic inspection. Every day, the coaster must be thoroughly inspected before it goes into operation.
Before the ride is open to the public, the cars are filled with weighted sandbags and sent through several circuits to ensure everything is operating properly. Government safety inspectors check make a final review before they give approval to operate.
The current trend to higher, longer, and faster coasters will probably continue for the near future. This is especially true now that roller coasters have become popular in Europe, Asia, and many other foreign countries. In the meantime, coaster designers will be looking for new ways to give riders a physical and visual thrill.
Where to Learn More
Bennett, David. Roller Coaster: Wooden and Steel Coasters, Twisters, and Corkscrews. Edison, NJ: Chartwell Books, 1998.
Cook, Nick. Roller Coasters, or, I Had So Much Fun, I Almost Puked. Minneapolis, MN: Carolrhoda Books, Inc., 1998.
Lindsay, D. "Terror Bound." American Heritage (September 1998): 76-89.
Ruben, P. L. "Scream Machines." Popular Mechanics (August 1998): 80-83.
World of Coasters. http://www.rollercoaster.com (November 29, 1999).
"Roller Coaster." How Products Are Made. . Encyclopedia.com. (September 10, 2018). http://www.encyclopedia.com/manufacturing/news-wires-white-papers-and-books/roller-coaster
"Roller Coaster." How Products Are Made. . Retrieved September 10, 2018 from Encyclopedia.com: http://www.encyclopedia.com/manufacturing/news-wires-white-papers-and-books/roller-coaster
Modern Language Association
The Chicago Manual of Style
American Psychological Association
roll·er coast·er • n. an amusement park attraction that consists of a light railroad track with many tight turns and steep slopes, on which people ride in small fast open cars. ∎ fig. a thing that contains or goes through wild and unpredictable changes: a terrific roller coaster of a book. • v. (roll·er-coast·er) (also roll·er-coast) [intr.] move, change, or occur in the dramatically changeable manner of a roller coaster: the twentieth century fades behind us and history roller-coasters on.
"roller coaster." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (September 10, 2018). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/roller-coaster
"roller coaster." The Oxford Pocket Dictionary of Current English. . Retrieved September 10, 2018 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/roller-coaster
Modern Language Association
The Chicago Manual of Style
American Psychological Association
In the United States, approximately three hundred million people ride roller coasters every year.
A roller coaster is an amusement park ride made of a series of linked cars on a rail track supported by a wood or steel structure and shaped into rises, drops, twists, and turns. In the United States, approximately three hundred million people ride roller coasters every year.
In operation, the train of cars is pulled up a steep hill, called a lift hill, by a motorized linked chain. Anti-roll-back mechanisms consisting of steel bars called anti-rollbacks (found on the track) and metal hooks called dogs (found under the cars) prevent a climbing train from rolling backward. If the train starts going backward, the anti-rollback dogs latch on to the steel bars to stop further movement. When the cars reach the top of the hill, they are released by the chain and are pulled downward by gravity through a series of drops, rises, and turns. Finally, the cars are slowed and then stopped at the starting point, where the passengers get out, and new passengers get on.
The original roller coasters were ice slides in Russian fairs during the fifteenth and sixteenth centuries. The ride consisted of a steep incline of ice or a wooden slide covered with ice. Some rides had a few bumps for variation. A sand pile at the bottom of the slide stopped the sled from going any further.
Visitors from France are said to have borrowed the idea of the ride, calling it the Russian Mountains. Waxed wooden slides and wooden sleds with wheels were later built to afford year-round entertainment. By the early 1800s, the first roller coaster with a train of cars running on a track had become popular. As the popularity of the rides grew, operators built faster and more exciting coasters. However, the operators did not provide safety devices, and accidents frequently occurred. By the mid-1850s, people had lost interest in the rides, and they were closed down.
Mules on roller coasters
The American version of the first roller coaster started out as mine cars used to carry coal from the mountains down to barges in a canal below. In the early 1800s, the Mauch Chuck Switchback Railway in Pennsylvania used mules to haul empty mine cars up the mountain. The loaded cars and a separate car for the mules rode 18 miles (29 kilometers) downhill by gravity alone. Later on, steam engines replaced the mules.
When mining operations changed in 1874, the railroad began hauling sightseers instead of coal. A hotel and restaurant on the mountain added to the popularity of the one-dollar ride, which continued operation up to 1938 when the railroad closed.
Early roller coasters
In 1884, LaMarcus Thompson (1848–1919) built the Gravity Pleasure Switchback Railway ride in Coney Island, New York. This was the earliest true roller coaster, made of wood on a wooden support structure. Passengers climbed up the stairs and got on a car that faced sideways. The car was pushed down an incline, coasting over a series of gentle hills. For the return trip, the riders switched to another car, which was similarly operated. The nickel ride, which was made for sightseeing, traveled at a speed of six miles per hour.
In late 1884, Charles Alcoke built the second coaster in Coney Island. The Serpentine Railway was the first oval track and traveled at twelve miles per hour. The following year, Phillip Hinckle built the Gravity Pleasure Road, using a chain lift to haul the cars up the first hill, allowing the riders to board on the ground. The cars also faced forward.
By the 1920s, over 1,500 wooden roller coasters were operating in the United States. However, the economic hardships of the Great Depression (1929–1933) and the wartime material shortages during World War II (1939–1945) put an end to the roller coaster craze.
Modern roller coasters
It took more than two decades for roller coasters to make a comeback. In 1959, Walt Disney (1901–1966) opened the Matterhorn Bobsled ride at Disneyland in Anaheim, California. This was the first tubular steel coaster and consisted of cars that were constructed like bobsleds. However, it took the construction of John Allen's (1907–1979) new wooden coaster in 1972—Racer at Kings Island near Cincinnati, Ohio—to revive interest in roller coasters. Since then, higher and faster coasters have been constructed each year. As of early 2002, Superman: The Escape (Valencia, California), opened in 1997, was the fastest (100 miles per hour, or 161 kilometers) and tallest (415 feet, or 126 meters) roller coaster in the United States.
The two types of roller coasters are wooden and steel coasters. Wooden coasters, sometimes called "woodies," use huge supporting structures consisting of horizontal beams supported by two pair of spreading legs at each end. These are called trestle-style structures. The wood, typically made of Douglas fir or southern yellow pine, is painted or treated to prevention deterioration. The wooden parts are supported on concrete foundations and are joined with bolts and nails. Steel plates are used to strengthen the joints where the wooden parts meet.
A large number of parts make up a wooden coaster. For example, the American Eagle in Six Flags Great America, Gurnee, Illinois, used 2,000 concrete foundations; 1.6 million feet (487,000 meters) of wood; 60,720 bolts; and 30,600 pounds (13,910 kilograms) of nails; and 9,000 gallons (34,065 liters) of paint.
Steel coasters may use the same trestle-style supporting structures as those in wooden coasters. They may also use thick steel tubes for support. The tubular steel tracks are prefabricated, or manufactured in a factory, as large curved sections and later brought to the construction site for assembly. All steel surfaces are painted.
Like wooden coasters, steel coasters consist of numerous parts. For example, the Pepsi Max Big One coaster at Blackpool Pleasure Beach in Blackpool, England, used 1,270 piles driven into the sandy soil for the foundation; 2,215 tons (2,010 metric tons) of steel; and 60,000 bolts. The painted surfaces comprise 42,000 square yards (35,087 square meters).
The track and lift chain on both types of coasters are made of steel. The car bodies may be made of aluminum or fiberglass. The car wheels may be made of urethane or some other long-wearing, quiet-running material. The cars usually have steel axles (bars on which wheels turn) and substructures.
The designers first determine what kind of riders will use the coaster. Children typically like coasters that are slow and have hills, drops, and curves that are gentle. On the opposite end are riders who enjoy being "scared to death," seeking out coasters that provide extreme speeds, heights, and turns. In between these two groups are those riders who, while wanting the sensational experience of a roller coaster ride, prefer moderate speeds and heights.
The designers have to decide how much ground and air spaces are needed for a particular roller coaster. They check out possible sites, as well as access roads, trees, lakes, and power lines. In cases where the amusement park has other rides or where the available space is small, designers have to figure out ways to fit the new roller coaster into the surroundings. Some coasters have been designed to thread their way through existing rides and walkways.
In a typical roller coaster, riders sit in cars. Steel construction has allowed for variations on this basic coaster ride. One model has passengers standing up instead of sitting down. Another type of coaster hangs from the track, giving the sensation of flying. This particular design, however, does not allow for inversion (part of the track that turns riders upside down) as it could be dangerous. Bobsled coasters have no track at all. Cars roll free in a chute, like a bobsled run.
Using a computer, the designers plan the arrangement of the hills, drops, and turns. The height of the first hill, or lift hill, must be calculated to give the cars enough energy to push them all the way through the ride and back to the station. A coaster does not have an engine to keep the cars going. It relies on the energy gathered as it climbs the lift hill.
The designers calculate the forces that the loaded cars exert on the tracks to ensure that the support structure is adequate. They also calculate the gravitational forces (also called g forces) exerted on the passengers at different points of the ride. Roller coasters are possible because of gravity, the force that pulls objects toward the earth. Gravitational forces, measured in g's, give people weight. The earth exerts a g force of 1 g when a person is standing on the ground. A person feels heavier when the g force is higher than 1 g and lighter when the g force is lower than 1 g. When a roller coaster climbs uphill, the g force on the person increases, and his weight gets heavier. For example, if a person weighs 100 pounds (45.5 kilograms), a g force of 2 g's would exert 200 pounds (91 kilograms) of force on that person. In the United States, coasters generally exert no more than 3.5 g's, which is the limit that most people can take.
Next, the designers decide what features to add to make the particular roller coaster different from others. They may make the first climb higher or the speed of the lift chain slower to add excitement to the anticipated drop. The first drop is usually the highest and, therefore, the fastest and scariest. Other drops can be designed with a double dip, in which a hill has two separate drops by adding a short flattened section midway down the hill. Some drops, called slammers, have unexpected flat or upturned sections that slam passengers down into their seats.
The Manufacturing Process
Wooden roller coasters are usually constructed piece by piece in the amusement park. For steel roller coasters, the track sections are prefabricated in a factory, then transported to the site and put together. The following are the typical steps for manufacturing classic wooden coasters and modern steel coasters.
Preparing the construction site
1 The area where the roller coaster will be built has to be cleared and prepared. Roller coasters are usually built when the amusement park is closed for the season. If construction has to be done when the park is open, the area is fenced to keep people off the site.
2 Existing structures, vegetation, or utilities are removed or demolished. Any holes left are filled in with dirt.
FLOATING IN AIR
When the train reaches the top of a hill or a loop and then plunges downward, the riders may feel as if they are floating in air. This sensation, called airtime, also gives the feeling of coming out of one's seat. Airtime is the result of a decrease in the gravitational forces that pull at the body.
3 The holes for the foundation of the support structure are laid out and then drilled or dug. Strong wooden forms (molds) are constructed to hold the concrete for the foundation points. If the soil is sandy, instead of concrete, large wooden columns may be driven into the ground to serve as foundations. Concrete is transported to the site in mixer trucks and pumped into the forms. Connector plates are imbedded into the concrete on top of the foundation so that supports can be attached to the foundation.
Erecting the main support structure
4 After the foundation is laid, the main support structure is built. The supports, like the other parts of the steel coasters, are prefabricated. In the factory, the pieces for each support are cut and welded into the required shape. If a more complicated three-dimensional bend is required, a computer-controlled hydraulic (operated by water under pressure) tube bender is used.
To built the supports for wooden coasters, unfinished lumber is transported to the site, cut into pieces, and assembled. For both types of coasters, the lower portions of the main supports are lifted by a crane and attached to the connector plates on the foundation points.
5 The lower supports are temporarily braced (held steady by a framework) while the upper sections are attached. The work continues until the main support structure is complete.
Installing the track
6 On steel coasters, the track sections are manufactured in a factory with the stanchions (vertical supports) and tubular tracks welded to the track supports. At the site, the track sections are lifted into place, and the track ends are slid together. The sections are bolted to the main support structure and to each other.
On wooden coasters, wooden crosstie beams are placed across the top of the main support structures along the whole length of the ride. The base for the rails consists of six to eight layers of flat wooden boards bonded together and placed lengthwise in two rows on top of the crosstie beams. The rails themselves are formed from long, flat strips of steel screwed into the wooden base.
7 On steel coasters, walkways and handrails are welded in place along the outside of the track. This gives easy access for servicing the coaster and for emptying the ride of passengers in case of emergency. On wooden coasters, the parts of the crosstie beams outside of the tracks serve as walkways, and handrails are put in place.
8 The lift chain and anti-roll-back mechanisms are installed on the lift hill. Unlike the brake system that is built into an automobile, the brake system of a roller coaster is built into the track and controlled by computers. Braking devices, located at the end of the track and at certain locations throughout the track, are installed.
Assembling the cars
9 The cars that are connected to make a train are made in the factory. The subframe pieces, or the pieces of the metal frame on which the car's body is built, are cut and welded. The bodies are stamped (cut out by forcing into or against a mold) from aluminum or formed in fiberglass, then fastened to the subframes. The cushions may be cut from foam, mounted on a base, and covered with material.
Three kinds of wheels are used in the cars. The road wheels that sit on top of the track support the weight of the cars. Underneath the track are the upstop wheels, also called the underfriction wheels. They lock on to the cars, keeping them from jumping off the track. The third set of wheels called guide wheels inside and outside of the running rail "guide" a roller coaster along the path of the tracks. All these wheels are bolted in place with locking fasteners.
Other safety devices, including anti-rollback dogs and braking fins are also fitted under the cars. The anti-rollback dogs are the metal hooks that keep a climbing train from rolling backward by grasping the anti-rollbacks, or steel bars, on the track. In coasters that use a braking system consisting of fin brakes, a braking fin is attached to the bottom of the car. The fin-brake unit consists of two rectangular metal plates installed onto the track and the car braking fin, another rectangular plate. Computerized sensors on the track cause the fin brakes to "squeeze" the car braking fin, making the train of cars slow down or stop.
Finishing the ride
10 After the main construction is finished, electrical wiring is installed for the lighting. The ride may be painted. The boarding station is constructed, and the signs and landscaping are added.
The design and construction of roller coasters are covered by government safety rules. The materials have to be strong enough to support the weight of the ride and riders. Government inspectors periodically inspect the various phases of the construction.
JOHN A. MILLER
John A. Miller (1874–1941) invented many of the safety devices that are still used in today's roller coasters. The underfriction wheels, also called the upstop wheels, allow the loops and steep climbs and dips that otherwise would not be possible because of the danger of the wheels leaping off the track. The safety chain dog, also called the anti-rollback dog, prevents the cars from rolling backward should the chain lift break. The clickety-clack sound riders hear when the cars go uphill is caused by this safety device.
To make sure the ride is safe, the cars are filled with sandbags (to simulate the weight of riders) and sent through several rides around the entire track. The government investigators conduct a final check before allowing the ride to open to the public.
Higher, faster, and longer roller coasters continue to be built in the United States. Roller coasters have also become popular in other countries. The Dodonpa roller coaster in Fujikyu Highland, Japan, which opened in December 2001, has already surpassed Superman: The Escape as the fastest steel coaster in the world.
Designers may come up with more looping wooden coasters, which are not as easy to design as steel coasters. The Son of Beast coaster in Kings Mills, Ohio, is presently the only looping wooden coaster in the world. Opened in May 2000, it holds the worldwide record for the tallest (218 feet, or 66.4 meters) and fastest (78.4 miles per hour, or 126.2 kilometers per hour) wooden coaster.
Designers may introduce new designs of roller coasters called prototypes. In January 2002, the world's first four-dimensional coaster called X opened to the public at the Six Flags Magic Mountain in Valencia, California. The cars, which spin the riders 360 degrees forward and backward, are on an axis separate from the train's main movement. Designers of Thunderhawk, which opened on April 6, 2002, in Kansas City, Missouri, have incorporated several new features, including a fountain with computerized programs that will subject gondola riders to different degrees of soaking.
- A beam that is laid across the track to support the rails.
- double dip:
- A drop that is interrupted by a short flattened section midway down the hill, thereby increasing the airtime, or feeling of weightlessness.
- A lightweight, strong material made from compressed glass fibers.
- g force:
- Stands for gravitational force, which is a measurement of the amount of gravity exerted on the passengers at different points of the roller coaster ride.
- The force that pulls objects down toward the earth.
- Part of the roller coaster track that turns riders upside down.
- lift hill:
- A steep hill with a linked chain or other mechanism that carries the roller coaster to the top. This hill is usually the first and highest on a roller coaster.
- Pairs of steel bars at the edges of tracks, just like those on a railroad track.
- A sudden, hard drop that slams passengers down into their seats, giving riders a feeling of weightlessness.
- The rails on which the roller coaster travels.
For More Information
Bennett, David. Roller Coaster: Wooden and Steel Coasters, Twisters, and Corkscrews. Edison, NJ: Chartwell Books, 1998.
Cook, Nick. Roller Coasters, or, I had So Much Fun, I Almost Puked. Minneapolis, MN: Carolrhoda Books, Inc., 1998.
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"Roller Coaster." CDs, Super Glue, and Salsa: How Everyday Products Are Made: Series 3. . Retrieved September 10, 2018 from Encyclopedia.com: http://www.encyclopedia.com/education/culture-magazines/roller-coaster