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Signal Passed At Danger
A signal passed at danger (SPAD), known in the United States as a stop signal overrun and in Canada as passing a stop signal, is an event on a railway where a train passes a stop railway signal, signal without authority. In the United States and Canada, this may be known colloquially as ''wikt:run a red light, running a red'', though this idiom principally refers to automobiles passing red traffic signals. The name derives from red Railway_signal#Colour_light_signals, colour light signals and horizontal Railway semaphore signal, semaphore signals in the United Kingdom, which are said to be ''at danger'' when they indicate that trains must stop (also known as the signal being ''on''). This terminology is not used in North America where not all red signals indicate stop. In the UK, the alternative description signal passed at red (S.P.A.R.) is used where a signal changes to red in front of a train due to either a technical fault or in an emergency, such that the train is unable t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rail Safety And Standards Board
The Rail Safety and Standards Board (RSSB) is a British independent company limited by guarantee. Interested parties include various rail industry organisations, including Network Rail, train operating companies (TOCs), and rolling stock companies (ROSCOs). The RSSB operates as a not-for-profit entity, its primary purpose being to bring about improved health and safety performance throughout Britain's railway network. In the fulfilment of this purpose, the Board undertakes numerous safety-focused monitoring and continuous improvement programmes, such as the railway supplier quality assurance schemRISQSand the Confidential Incident Reporting & Analysis System (CIRAS). It is also works with operators to identify and address risks, and is responsible for the updating and issuing of the British Railway Rule Book, amongst its other activities. The majority of Britain's train operators are obliged to be members of the RSSB, and to ensure compliance with their membership obligation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overlap (railway Signalling)
An overlap in railway signalling is the length of track beyond a stop signal that is proved to be clear of vehicles in the controls of the previous signal, as a safety margin. Overview Enough braking distance is provided to allow a train to comfortably stop at the stop signal, but should it fail to do so for any reason (fog, smoke, slippery rails, brake failure, inattention by driver, etc.) there is still some distance to allow the train to stop short of any obstruction, such as another train. Length The length of an overlap may be a nominal length, or else calculated on the full emergency braking distance for the gradients and speeds for that particular section of line. Two signal protection If the overlap is long enough to extend from one stop signal to the next, then the effect is to provide two signal protection (or "double blocking"), with the first signal having a full overlap, and the second signal having a short overlap. With two signal protection, only one trac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Passed At Danger In The United Kingdom; Terminology And Procedures
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' includes audio, video, speech, image, sonar, and radar as examples of signal. A signal may also be defined as observable change in a quantity over space or time (a time series), even if it does not carry information. In nature, signals can be actions done by an organism to alert other organisms, ranging from the release of plant chemicals to warn nearby plants of a predator, to sounds or motions made by animals to alert other animals of food. Signaling occurs in all organisms even at cellular levels, with cell signaling. Signaling theory, in evolutionary biology, proposes that a substantial driver for evolution is the ability of animals to communicate with each other by developing ways of signaling. In human engineering, signals are typi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chiltern Railways
Chiltern Railways, formally The Chiltern Railway Company Limited, is a British train operating company that has operated the Chiltern Railways franchise since July 1996. Since 2009, it has been a subsidiary of Arriva UK Trains. Chiltern Railways was founded as M40 Trains by a group of ex- British Rail managers backed by John Laing and 3i; in June 1996, it was announced that M40 Trains had been awarded the Chiltern Railways franchise. On 21 July 1996, it took over operations from British Rail. The company promptly commenced the redoubling of the Chiltern Main Line under the ''Evergreen'' initiative and ordered the Class 168 ''Clubman'' diesel multiple units (DMUs) to supplement its ex-British Rail fleet. Following the awarding of a 20-year franchise to Chiltern Railways in August 2000, Evergreen phase 2 works begun to raise line speeds around Beaconsfield, built two new platforms at its London Marylebone terminus. In January 2010, a £250 million upgrade package was agreed fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Western Railway (train Operating Company)
Great Western Railway (GWR) is a British train operating company owned by FirstGroup that operates the Greater Western passenger railway franchise. It manages 197 stations and its trains call at over 270. GWR operates long-distance inter-city services along the Great Western Main Line to and from the West of England and South Wales, inter-city services from London to the West Country via the Reading–Taunton line, and the ''Night Riviera'' sleeper service between London and Penzance. It also provides commuter and outer-suburban services from its London terminus at Paddington to West London, the Thames Valley region including parts of Berkshire, parts of Buckinghamshire and Oxfordshire; and regional services throughout the West of England and South Wales to the South coast of England. Great Western Railway also provides and maintains the Electrostar Class 387 fleet for Heathrow Express. The company began operating in February 1996 as Great Western Trains, as part of the pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsleep
A microsleep is a sudden temporary episode of sleep or drowsiness which may last for a few seconds where an individual fails to respond to some arbitrary sensory input and becomes unconscious.International Classification of Sleep Disorders, , page 343Poudel, G. R., Innes, C. R., Bones, P. J., Watts, R., & Jones, R. D. (2012) Losing the struggle to stay awake: Divergent thalamic and cortical activity during microsleeps. Human Brain Mapping: 00:000-000 MSs occur when an individual loses and regains awareness after a brief lapse in consciousness, often without warning, or when there are sudden shifts between states of wakefulness and sleep. In behavioural terms, MSs may manifest as droopy eyes, slow eyelid-closure, and head nodding. In electrical terms, microsleeps are often classified as a shift in electroencephalography (EEG) during which 4–7 Hz (theta wave) activity replaces the waking 8–13 Hz (alpha wave) background rhythm. MSs frequently occur as a result of slee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleep Apnea
Sleep apnea, also spelled sleep apnoea, is a sleep disorder in which pauses in breathing or periods of shallow breathing during sleep occur more often than normal. Each pause can last for a few seconds to a few minutes and they happen many times a night. In the most common form, this follows loud snoring. There may be a choking or snorting sound as breathing resumes. Because the disorder disrupts normal sleep, those affected may experience sleepiness or feel tired during the day. In children, it may cause hyperactivity or problems in school. Sleep apnea may be either obstructive sleep apnea (OSA), in which breathing is interrupted by a blockage of air flow, central sleep apnea (CSA), in which regular unconscious breath simply stops, or a combination of the two. OSA is the most common form. OSA has four key contributors; these include a narrow, crowded, or collapsible upper airway, an ineffective pharyngeal dilator muscle function during sleep, airway narrowing during sleep and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronic Condition
A chronic condition is a health condition or disease that is persistent or otherwise long-lasting in its effects or a disease that comes with time. The term ''chronic'' is often applied when the course of the disease lasts for more than three months. Common chronic diseases include diabetes, functional gastrointestinal disorder, eczema, arthritis, asthma, cancer, chronic obstructive pulmonary disease, Lyme disease, autoimmune diseases, genetic disorders and some viral diseases such as hepatitis C and acquired immunodeficiency syndrome. An illness which is lifelong because it ends in death is a terminal illness. It is possible and not unexpected for an illness to change in definition from terminal to chronic. Diabetes and HIV for example were once terminal yet are now considered chronic due to the availability of insulin for diabetics and daily drug treatment for individuals with HIV which allow these individuals to live while managing symptoms. In medicine, ''chronic'' conditio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functioning properly. Signs and symptoms of a stroke may include an inability to move or feel on one side of the body, problems understanding or speaking, dizziness, or loss of vision to one side. Signs and symptoms often appear soon after the stroke has occurred. If symptoms last less than one or two hours, the stroke is a transient ischemic attack (TIA), also called a mini-stroke. A hemorrhagic stroke may also be associated with a severe headache. The symptoms of a stroke can be permanent. Long-term complications may include pneumonia and loss of bladder control. The main risk factor for stroke is high blood pressure. Other risk factors include high blood cholesterol, tobacco smoking, obesity, diabetes mellitus, a previous TIA, end-st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myocardial Infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck or jaw. Often it occurs in the center or left side of the chest and lasts for more than a few minutes. The discomfort may occasionally feel like heartburn. Other symptoms may include shortness of breath, nausea, feeling faint, a cold sweat or feeling tired. About 30% of people have atypical symptoms. Women more often present without chest pain and instead have neck pain, arm pain or feel tired. Among those over 75 years old, about 5% have had an MI with little or no history of symptoms. An MI may cause heart failure, an irregular heartbeat, cardiogenic shock or cardiac arrest. Most MIs occur due to coronary artery disease. Risk factors include high blood pressure, smoking, diabetes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute (medicine)
In medicine, describing a disease as acute denotes that it is of short duration and, as a corollary of that, of recent onset. The quantification of how much time constitutes "short" and "recent" varies by disease and by context, but the core denotation of "acute" is always qualitatively in contrast with " chronic", which denotes long-lasting disease (for example, in acute leukaemia and chronic leukaemia). In addition, "acute" also often connotes two other meanings: sudden onset and severity, such as in acute myocardial infarction (AMI), where suddenness and severity are both established aspects of the meaning. It thus often connotes that the condition is fulminant (as in the AMI example), but not always (as in acute rhinitis, which is usually synonymous with the common cold). The one thing that acute MI and acute rhinitis have in common is that they are not chronic. They can happen again (as in recurrent pneumonia, that is, multiple acute pneumonia episodes), but they are not t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
