|
Track Circuit
A track circuit is an electrical device used to prove the absence of a train on a block of rail tracks to control railway signals. An alternative to track circuits are axle counters. Principles and operation The basic principle behind the track circuit lies in the connection of the two rails by the wheels and axle of locomotives and rolling stock to short an electrical circuit. This circuit is monitored by electrical equipment to detect the absence of the trains. Since this is a safety appliance, fail-safe operation is crucial. Hence the circuit is designed to indicate the presence of a train when failures occur. On the other hand, false occupancy readings are disruptive to railway operations and must be minimized. Track circuits allow railway signalling systems to operate semi-automatically, by displaying signals for trains to slow or stop in the presence of occupied track ahead of them. They help prevent dispatchers and operators from causing accidents, both by informin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Track Circuit Robinson 1874
Track or Tracks may refer to: Routes or imprints * Ancient trackway, any track or trail whose origin is lost in antiquity * Animal track, imprints left on surfaces that an animal walks across * Desire path, a line worn by people taking the shortest/most convenient route across fields, parks or woods * Forest track, a track (unpaved road) or trail through a forest * Fossil trackway, a type of trace fossil, usually preserving a line of animal footprints * Trackway, an ancient route of travel or track used by animals * Trail * Vineyard track, a land estate (defined by law) meant for the growing of vine grapes Arts, entertainment, and media Films * Tracks (1922 film), ''Tracks'' (1922 film), an American silent Western film * Tracks (1976 film), ''Tracks'' (1976 film), an American film starring Dennis Hopper * Tracks (2003 film), ''Tracks'' (2003 film), an animated short film * Tracks (2013 film), ''Tracks'' (2013 film), an Australian film starring Mia Wasikowska * The Track (film), '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Railway Signalling
Railway signalling (), or railroad signaling (), is a system used to control the movement of railway traffic. Trains move on fixed rails, making them uniquely susceptible to collision. This susceptibility is exacerbated by the enormous weight and inertia of a train, which makes it difficult to quickly stop when encountering an obstacle. In the UK, the Regulation of Railways Act 1889 introduced a series of requirements on matters such as the implementation of interlocked block signalling and other safety measures as a direct result of the Armagh rail disaster in that year. Most forms of train control involve movement authority being passed from those responsible for each section of a rail network (e.g. a signalman or stationmaster) to the train crew. The set of rules and the physical equipment used to accomplish this determine what is known as the ''method of working'' (UK), ''method of operation'' (US) or ''safe-working'' (Aus.). Not all these methods require the use of p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alstom
Alstom SA () is a French multinational rolling stock manufacturer which operates worldwide in rail transport markets. It is active in the fields of passenger transportation, signaling, and locomotives, producing high-speed, suburban, regional and urban trains along with trams. The company and its name (originally spelled Alsthom) was formed by a merger between the electric engineering division of Société Alsacienne de Constructions Mécaniques (Als) and Compagnie Française Thomson-Houston (thom) in 1928. Significant acquisitions later included the Constructions Électriques de France (1932), shipbuilder Chantiers de l'Atlantique (1976), and parts of ACEC (late 1980s). A merger with parts of the British General Electric Company formed GEC Alsthom in 1989. Throughout the 1990s, the company expanded its holdings in the rail sector, acquiring German rolling stock manufacturer Linke-Hofmann-Busch and Italian rail signaling specialist Sasib Railways. In 1998, GEC Alsthom was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Railway Signal
General Railway Signal Company (GRS) was an American manufacturing company located in the Rochester, New York area. GRS was focused on railway signaling equipment, systems and services. The company was established in 1904 and became part of Alstom Transport in 1998. GRS was a member of the Dow Jones Industrial Average from 1928 to 1930. History GRS was founded in 1904 with the merger of three companies (Pneumatic Signal Company of Rochester, New York; Taylor Signal Co. of Buffalo, New York and Standard Railroad Signal Company of Arlington, New Jersey). In 1923 GRS acquired the Federal Signal Company of Albany, New York. General Railway Signal was one of the 30 stocks when the Dow Jones Industrial Average was expanded from a 20-stock average on October 1, 1928. It was replaced in the DJIA by Liggett & Myers on July 18, 1930. In 1965, General Signal Corporation (GSX) was created with the intent to diversify into areas other than railway signaling. GRS was a wholly owned subsidia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shanghai Metro
The Shanghai Metro (; Shanghainese: ''Zaon6he5 Di6thiq7'') is a rapid transit system in Shanghai, operating urban and suburban transit services to 14 of its 16 List of township-level divisions of Shanghai, municipal districts and to the neighboring township of Huaqiao metro station (Kunshan), Huaqiao, in Kunshan, Jiangsu Province. Forming the vast majority of the broader, multi-operator Shanghai rail transit network, the Shanghai Metro system is the world's List of metro systems, second longest metro system by route length, totaling and the List of metro systems, second largest system by number of stations, with List of Shanghai Metro stations, 508 stations across 19 lines. It also ranks Metro systems by annual passenger rides, first in the world by annual ridership, with 3.88 billion rides delivered in 2019. The last daily ridership record was set on 9 March 2024, at 13.39 million rides. Since the COVID-19 pandemic, pandemic, ridership still routinely stands at over 10 millio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Impedance
In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of Electrical_resistance, resistance and Electrical_reactance, reactance in a electrical circuit, circuit. Quantitatively, the impedance of a two-terminal Electrical element, circuit element is the ratio of the phasor, complex representation of the Sine wave, sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. In general, it depends upon the frequency of the sinusoidal voltage. Impedance extends the concept of Electrical resistance, resistance to alternating current (AC) circuits, and possesses both Euclidean vector, magnitude and Phase (waves), phase, unlike resistance, which has only magnitude. Impedance can be represented as a complex number, with the same units as resistance, for which the SI unit is the ohm (). Its symbol is usually , and it may be represented by writing its magnitude and phase in the Polar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cab Signalling
Cab signalling is a railroad, railway safety system that communicates track status and condition information to the cab (locomotive), cab, crew compartment or driver's compartment of a locomotive, railcar or multiple unit. The information is continually updated giving an easy to read display to the train driver or Railroad engineer, engine driver. The simplest systems display the trackside signal, while more sophisticated systems also display allowable speed, location of nearby trains, and dynamic information about the track ahead. Cab signals can also be part of a more comprehensive train protection system that can automatically apply the brakes stopping the train if the operator does not respond appropriately to a dangerous condition. The main purpose of a signal system is to enforce a safe separation between trains and to stop or slow trains in advance of a restrictive situation. The cab signal system is an improvement over the Railway signal, wayside signal system, where vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Frequency
An audio frequency or audible frequency (AF) is a periodic vibration whose frequency is audible to the average human. The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch. The generally accepted standard hearing range for humans is 20 to 20,000 Hz (20 kHz). In air at atmospheric pressure, these represent sound waves with wavelengths of to . Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Sound waves that have frequencies below 20 Hz are called infrasonic and those above 20 kHz are called ultrasonic. Sound propagates as mechanical vibration waves of pressure and displacement, in air or other substances. In general, frequency components of a sound determine its "color", its timbre. When speaking about the frequency (in singular) of a sound, it means the property that most determines its pitch. Higher pitches have higher frequency, and low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow through semiconductors, electrical insulation, insulators, or even through a vacuum as in electron beam, electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A archaism, term formerly used for this type of current was galvanic current. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', as when they modify ''Electric current, current'' or ''voltage''. Direct current may be converted from an alternating current supply by use of a rectifier, which contains Electronics, electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be converted into alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternating Current
Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, Fan (machine), fans and electric lamps into a wall socket. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', respectively, as when they modify ''Electric current, current'' or ''voltage''. The usual waveform of alternating current in most electric power circuits is a sine wave, whose positive half-period corresponds with positive direction of the current and vice versa (the full period is called a ''wave cycle, cycle''). "Alternating current" most commonly refers to power distribution, but a wide range of other appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traction Motor
A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, or electric multiple unit trains. Traction (engineering), Traction motors are used in electrically powered railway vehicles (electric multiple units) and other electric vehicles including electric milk floats, trolleybuses, elevators, roller coasters, and conveyor systems, as well as vehicles with electrical transmission systems (Diesel locomotive#Transmission types, diesel–electric locomotives, electric hybrid vehicles), and battery electric vehicles. Traction motor companies The word ''traction'' from Latin, being the Agent (grammar), agent noun of ''trahere'' "to pull" in the sense of "drawn" was used for the naming of traction engines developed circa 1870. The first experimental electric traction motor tramway of 1875 was rapidly developed internationally for city use. In the 19th century traction motor passenger car companies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Railway Electrification
Railway electrification is the use of electric power for the propulsion of rail transport. Electric railways use either electric locomotives (hauling passengers or Rail freight transport, freight in separate cars), electric multiple units (Passenger car (rail), passenger cars with their own motors) or both. Electricity is typically generated in large and relatively efficient electric power station, generating stations, transmitted to the railway network and distributed to the trains. Some electric railways have their own dedicated generating stations and electric transmission line, transmission lines, but most purchase power from an electric utility. The railway usually provides its own distribution lines, switches, and transformers. Power is supplied to moving trains with a (nearly) continuous electrical conductor, conductor running along the track that usually takes one of two forms: an overhead line, suspended from poles or towers along the track or from structure or tunnel cei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
