Introduction: You wait in line for what seems like forever and finally you take your seat. You pull the paddle bars so they fit snug against your shoulders. You reach the top and then comes the big drop. You start screaming or if you're daring you put your hands up and enjoy the ride. I'm of course speaking of roller coasters. Today I'm going to go over the history, the different types of roller coasters, the mechanics, and the most important part, safety of roller coasters. History The oldest roller coaster is believed to have originated from the so-called "Russian Mountains", which were specially constructed hills of ice, located around Saint Petersburg. Built in the 15th century, the slides were built to a height between 70 and 80 Some roller coasters move back and forth along the same section of track; these are known as shuttles and usually run the circuit once with riders moving forwards and then backwards through the same course. Safety: Many safety systems are applied in roller coasters. One of these is the block system. Most large roller coasters have the ability to run two or more trains at once, and the block system prevents these trains from colliding. In this 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. 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. Another key to safety is the control of the roller coaster's operating computers: programmable logic controllers (often called PLCs). A PLC detects faults associated with the mechanism and makes decisions to operate roller coaster elements (for e.g. lift, track-switches and brakes) based on configured state and operator actions. Periodic maintenance and inspection are required to verify structures and materials are
