intermittent and continuous ATP 101119 - irse.nl

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changeability of different manufacturers’ subsystems. These advances bring withthem additional systems integration, safety assurance and configurationmanagement issues, which then impact upon the competence requirements ofdesigners, maintainers and others.The complexity of train-borne train control systems, and the importance of goodconfiguration management, is exacerbated by the fact that the design configuration oftrains vary, even within fleets, and this may affect the configuration of the train controlsystem.Modern train control systems usually include design features to prevent themaintainer from making unauthorised changes to the configuration. These areprovided primarily to protect against safety hazards and will include features such ashardwired cab identification codes, pin-codes (for plug-in components), checksums(for uploading of new software/data) and access restrictions (to prevent unauthorisedusers from using diagnostic and programming devices). But there will be aspects ofthe configuration that have no such defences other than relying on the competenceof the individual making the change.Differences Between Train Control SystemsWhatever their superficial similarities, not all train-borne train control systems arethe same in terms of their design and modes of operation, and it is helpful to beaware of the significant differences between them.We have already referred to one key difference, namely the approach taken bysystem designers to the achievement of acceptable levels of safety and availability,by the use of duplication/redundancy. The table below provides a list of summary ofthe most significant differences between systems, including the duplication/redundancy feature.FunctionExamples of Different approaches toachieving the functionMovement Authority • Distance Based (target stopping location)vs• Speed Based (e.g. speed code / targetspeed)Speed and Location Determination • Tacho-generators• Doppler Radar• Accelerometers• Loop Crossovers• TranspondersTrack / Train Communication • Digital Radio• Wave-Guide Systems• Inductive Loops• Running Rail TranspondersRedundancy • 2oo2 systems• 2oo3 systems• hot / warm / cold standbyGeographical Data • Trackside, transmitted to train as required• Train-borne (ATP and ATO)23
Examplesof ATP/ATC systemsLZB As Example Of A Continuous SystemThe LZB system was specified by UIC in the 1960s. A first implementation wasbuilt between Augsburg an Munich in 1965, where a maximum speed of 200 kph wasdemonstrated in passenger traffic. In 1972, a first line between Hamburg and Bremenwas taken into operation, which was based on a 2-out-of-3 computer system. Sincethen, all high speed lines in Germany were equipped with this system. Spain andAustria also adopted the computer based LZB system and lines in both countries arein operation.System SummaryIn the LZB system, all fixed data (i.e. line geography, permanent speedrestrictions) are stored in the LZB centre. The interlocking systems forward signalaspects, point settings and other element data to the control centre, the trains withinthe range of the system transmit their specific data, e.g. train length, train position,actual speed, etc.From this data the control centre determines for each train the target values suchas distance to stopping point which then are converted on board to a maximumpermissible speed. Since signal settings for several block sections ahead areforwarded, the maximum speed can be increased and the maximum braking distancecan be longer than the signal aspects of existing lineside signalling would allow.Operation Of The LZB SystemIn the LZB system stationary trackside information is combined with informationfrom mobile train-borne equipment. The resulting information is transmitted to thevehicles via inductive line loops. An inductive loop is formed between the rails bymeans of a cable laid according to installation standard B3 (UIC Standard ORE A46).The maximum logical loop length is 12.7 km. The conductors are transposedevery 100 m for compensating electrical characteristics as well as for determining thephysical positions of the trains. The on-board equipment senses the phase changewhen passing a transposition. The number of transpositions passed is counted.LZB TransmissionThe position of a train is transmitted to the control centre by indicating thenumber of 100 m-sections traversed by the front of the train (coarse positions). The24
Page 1 and 2: An Introduction to Intermittent and
Page 3 and 4: level the degree of safety is also
Page 5 and 6: affordable at all. In literature, e
Page 7 and 8: contradiction stems from the fact t
Page 9 and 10: GWML en Chiltern lines indicate tha
Page 11 and 12: Technology of ATP/ATC systemsThis c
Page 13 and 14: AWS MagnetsAn electrical transmissi
Page 15 and 16: Positioning of Indusi magnetsIn the
Page 17 and 18: end was traditionally done means of
Page 19 and 20: Train-borne System Architecture and
Page 21 and 22: Some parts of the train control sys
Page 23: fairly rare occurrence and, when th
Page 27 and 28: LZB data flowThe data available fro
Page 29 and 30: • signal aspects• point setting
Page 31 and 32: SELCAB transmissionThe number of se
Page 33 and 34: The first curve (indication curve)
Page 35 and 36: equired to reset the train-carried
Page 37 and 38: tests on sites located in different
Page 39 and 40: Current European ATP systemsThe fol
Page 41 and 42: • Level 2 is also based on conven
Page 43 and 44: signal information, it has to be ac
Page 45 and 46: Euroloop locationsLevel 2 would be
Page 47 and 48: information can be processed by the
Page 49 and 50: Ensuring safe and reliable operatio
Page 51 and 52: References and Bibliography1 ATP -
Page 53: Table 2 Numbers of existing ATP equ

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