Railway signalling

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Being guided by fixed rails, trains are uniquely susceptible to collision; furthermore, trains cannot stop quickly, and frequently operate at speeds that do not enable them to stop within sighting distance of the driver. This necessitated the establishment of strict guidelines for time keeping and railway chronometers in 1891 by the general time inspector Webb C. Ball of Cleveland, Ohio, USA. 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 safeworking (Aus.). Not all these methods require the use of physical signals and some systems are specific to single track railways.The earliest rail cars were first hauled by horses or mules. A mounted flagman on a horse preceded some early trains. Hand and arm signals were used to direct the rain drivers. Foggy and poor-visibility conditions gave rise to flags and lanterns. Wayside signalling dates back as far as 1832, and used elevated flags or balls that could be seen from afar.Contents1 Timetable operation 1.1 Timetable and train order 2 Block signalling 2.1 History of block signalling 2.2 Entering and leaving a manually-controlled block 2.3 Permissive and absolute blocks 2.4 Automatic block 2.4.1 Track circuits 2.4.2 Axle counters 2.5 Fixed block 2.6 Moving block 3 One engine in steam 4 Fixed signals 4.1 Mechanical signals 4.2 Colour light signals 4.3 Route signalling and speed signalling 4.4 Approach release 5 Safety systems 6 Cab signalling 7 Interlocking 8 Operating rules 8.1 Australian operating rules 8.2 North American operating rules 8.3 UK operating rules 8.4 Italian operating rules 9 References 10 See also 11 External links // Timetable operationThe simplest form of operation, at least in terms of equipment, is to run the system according to a timetable. A fixed schedule is drawn up with which every train crew must be familiar. Trains may only run on each section of track at their scheduled time, during which they have 'possession' and no other train is permitted to use the same section.When trains are running in opposite directions on a single-track railroad, meeting points ("meets") are scheduled, at which each train must wait for the other at a passing place. Neither train is permitted to move before the other has arrived. In the US the display of two green flags (green lights at night) is an indication that another train is following the first and the waiting train must wait for the next train to pass. In addition, the train carrying the flags gives eight blasts on the whistle as it approaches. The waiting train must return eight blasts before the flag carrying train may proceed.The timetable system has several disadvantages. First, there is no positive confirmation that the track ahead is clear, only that it is scheduled to be clear. The system does not allow for engine failures and other such problems, but the timetable is set up so that there should be sufficient time between trains for the crew of a failed or delayed train to walk far enough to set up warning flags, flares, and detonators or torpedoes (UK and US terminology, respectively) to alert any other train crew.A second problem is the system's inflexibility. Trains cannot be added, delayed, or rescheduled without advance notice.A third problem is a corollary of the second: the system is inefficient. To provide flexibility, the timetable must give trains a broad allocation of time to allow for delays, so the line is in the possession of each train for longer than is otherwise necessary.Nonetheless, this system permits operation on a vast scale, with no requirements for any kind of communication that travels faster than a train. Timetable operation was the normal mode of operation in North America in the early days of the railroad.Timetable and train orderSee also: Train order operationWith the advent of the telegraph in 1851, a more sophisticated system became possible because this provided a means whereby messages could be transmitted ahead of the trains. The telegraph...(and so on) To get More information , you can visit some products about headrest dvd system, turbo diesel system, . The Deluxe Computer Headset products should be show more here!