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Derailments In Africa
In rail transport, a derailment occurs when a rail vehicle such as a train comes off its rails. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway system and they are a potentially serious hazard. A derailment of a train can be caused by a collision with another object, an operational error (such as excessive speed through a curve), the mechanical failure of tracks (such as broken rails), or the mechanical failure of the wheels, among other causes. In emergency situations, deliberate derailment with derails or catch points is sometimes used to prevent a more serious accident. History The first recorded train derailment in history is known as the Hightstown Rail Accident in New Jersey that occurred on November 8, 1833. The train was traveling between Hightstown and Spotswood New Jersey and derailed after an axle broke on one of the carriages as a result of a journal box catching fire. The derailment resulted in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Train Wreck, Leavick, C
In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and transport people or freight. Trains are typically pulled or pushed by locomotives (often known simply as "engines"), though some are self-propelled, such as multiple units. Passengers and cargo are carried in railroad cars, also known as wagons. Trains are designed to a certain gauge, or distance between rails. Most trains operate on steel tracks with steel wheels, the low friction of which makes them more efficient than other forms of transport. Trains have their roots in wagonways, which used railway tracks and were powered by horses or pulled by cables. Following the invention of the steam locomotive in the United Kingdom in 1804, trains rapidly spread around the world, allowing freight and passengers to move over land faster and cheaper than ever possible before. Rapid transit and trams were first built in the late 1800s to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fatigue (material)
In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts of the fracture surface. The crack will continue to grow until it reaches a critical size, which occurs when the stress intensity factor of the crack exceeds the fracture toughness of the material, producing rapid propagation and typically complete fracture of the structure. Fatigue has traditionally been associated with the failure of metal components which led to the term metal fatigue. In the nineteenth century, the sudden failing of metal railway axles was thought to be caused by the metal ''crystallising'' because of the brittle appearance of the fracture surface, but this has since been disproved. Most materials, such as composites, plastics and ceramics, seem to experience some sort of fatigue-related failure. To aid in predicting t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coefficient Of Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into ''static friction'' ("stiction") between non-moving surfaces, and ''kinetic friction'' between moving surfaces. With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as asperities (see Figure 1). *Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. *Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces. *Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body. *Internal friction is the force resisting motion between the elements making up a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cone
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines connecting a common point, the apex, to all of the points on a base that is in a plane that does not contain the apex. Depending on the author, the base may be restricted to be a circle, any one-dimensional quadratic form in the plane, any closed one-dimensional figure, or any of the above plus all the enclosed points. If the enclosed points are included in the base, the cone is a solid object; otherwise it is a two-dimensional object in three-dimensional space. In the case of a solid object, the boundary formed by these lines or partial lines is called the ''lateral surface''; if the lateral surface is unbounded, it is a conical surface. In the case of line segments, the cone does not extend beyond the base, while in the case of half-lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cylinder (geometry)
A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite curvilinear surface in various modern branches of geometry and topology. The shift in the basic meaning—solid versus surface (as in ball and sphere)—has created some ambiguity with terminology. The two concepts may be distinguished by referring to solid cylinders and cylindrical surfaces. In the literature the unadorned term cylinder could refer to either of these or to an even more specialized object, the ''right circular cylinder''. Types The definitions and results in this section are taken from the 1913 text ''Plane and Solid Geometry'' by George Wentworth and David Eugene Smith . A ' is a surface consisting of all the points on all the lines which are parallel to a given line and which pass through a fixed plane curve in a pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2015 Philadelphia Train Derailment
On May 12, 2015, an Amtrak ''Northeast Regional'' train from Washington, D.C. bound for New York City derailed and wrecked on the Northeast Corridor near the Kensington neighborhood of Philadelphia, Pennsylvania. Of 238 passengers and 5 crew on board, 8 were killed and over 200 injured, 11 critically. The train was traveling at in a zone of curved tracks when it derailed. Some of the passengers had to be extricated from the wrecked cars. Many of the passengers and local residents helped first responders during the rescue operation. Five local hospitals treated the injured. The derailment disrupted train service for several days. The National Transportation Safety Board determined that the derailment was caused by the train's engineer (driver) becoming distracted by other radio transmissions and losing Situation awareness, situational awareness, and said that it would have been prevented by positive train control, a computerized speed-limiting system that was operational elsewh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santiago De Compostela Derailment
The Santiago de Compostela derailment occurred on 24 July 2013, when an Alvia high-speed train traveling from Madrid to Ferrol, in the north-west of Spain, derailed at high speed on a bend about outside of the railway station at Santiago de Compostela. Out of 222 people (218 passengers and 4 crew) on board, 143 were injured and 79 died."El fallecimiento de una estadounidense eleva a 79 los muertos en el accidente de Santiago" . Retrieved 28 July 2013. The train's |
Polmont Rail Accident
The Polmont rail accident, also known as the Polmont rail disaster, occurred on 30July 1984 to the west of Polmont, near Falkirk, in Scotland. A westbound push–pull train, push-pull express train travelling from Edinburgh to Glasgow struck a cow, which had gained access to the track through a damaged fence from a field near Polmont railway station. The collision caused all six carriages and the locomotive of the train to derail, killing 13people and injuring 61others. The accident led to a debate about the safety of push-pull trains on British Rail. Background The accident happened on one of the busiest Glasgow to Edinburgh via Falkirk Line, commuter lines in Scotland."13 Dead, 44 Injured After Train Hits Cow". Associated Press, New York City. 31 July 1984. At the time of the accident, British Rail passenger trains between Glasgow Queen Street and Edinburgh Waverley were operated by the push-pull train, push-pull technique with a single British Rail Class 47, British Rail Class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estray
Estray, in law, is any domestic animal found wandering at large or lost, particularly if the owner is unknown. In most cases this includes domesticated animals and not pets. Under early English common law, estrays were forfeited to the king or lord of the manor; under modern statutes, provision is made for taking up stray animals and acquiring either title to them or a lien for the expenses incurred in keeping them. A person taking up an estray has a qualified ownership in it, which becomes absolute if the owner fails to claim the animal within the statutory time limit. Whether the animal escaped through the owner's negligence or through the wrongful act of a third person is immaterial. If the owner reclaims the estray, he is liable for reasonable costs of its upkeep. The use of an estray during the period of qualified ownership, other than for its own preservation or for the benefit of the owner, is not authorized. Some statutes limit the right to take up estrays to certain classes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harmonic Oscillation
In classical mechanics, a harmonic oscillator is a system that, when displaced from its equilibrium position, experiences a restoring force ''F'' proportional to the displacement ''x'': \vec F = -k \vec x, where ''k'' is a positive constant. If ''F'' is the only force acting on the system, the system is called a simple harmonic oscillator, and it undergoes simple harmonic motion: sinusoidal oscillations about the equilibrium point, with a constant amplitude and a constant frequency (which does not depend on the amplitude). If a frictional force (damping) proportional to the velocity is also present, the harmonic oscillator is described as a damped oscillator. Depending on the friction coefficient, the system can: * Oscillate with a frequency lower than in the undamped case, and an amplitude decreasing with time (underdamped oscillator). * Decay to the equilibrium position, without oscillations (overdamped oscillator). The boundary solution between an underdamped oscillato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resonance
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillating force is applied at a resonant frequency of a dynamic system, the system will oscillate at a higher amplitude than when the same force is applied at other, non-resonant frequencies. Frequencies at which the response amplitude is a relative maximum are also known as resonant frequencies or resonance frequencies of the system. Small periodic forces that are near a resonant frequency of the system have the ability to produce large amplitude oscillations in the system due to the storage of vibrational energy. Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, orbital resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and reso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bogie
A bogie ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transport. A bogie may remain normally attached (as on many railroad cars and semi-trailers) or be quickly detachable (as the dolly in a road train or in railway bogie exchange); it may contain a suspension within it (as most rail and trucking bogies do), or be solid and in turn be suspended (as most bogies of tracked vehicles are); it may be mounted on a swivel, as traditionally on a railway carriage or locomotive, additionally jointed and sprung (as in the landing gear of an airliner), or held in place by other means (centreless bogies). In Scotland, the term is used for a child’s (usually home-made) wooden cart. While ''bogie'' is the preferred spelling and first-listed variant in various dictionaries, bogey and bogy are also used. Rai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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