intermittent and continuous ATP 101119 - irse.nl

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The German INDUSI system uses tuned circuits trackside and on board. Thecircuits are tuned to the same frequency and are detuned when a close couplingbetween both circuits takes place. The on-board resonant circuit is a serial resonantcircuit and is fed by an oscillator with its natural resonant frequency. A high oscillatorcurrent is therefore obtained. The oscillator current is monitored by the train borneequipment of INDUSI. When the train passes a trackside resonant circuit (stillreferred to as a magnet!), the coupling detunes the train borne equipment and theoscillator current decreases. The oscillator current is compared to a threshold andwhen the current falls under this threshold, a reaction is triggered. To cancel theoperation of the trackside resonant circuit in case of a go-aspect, the capacitor on thetrackside circuit is shorted by the signalling equipment and the train resonant circuitis only slightly damped when passing the signal, the threshold would not be touched.Indusi CoilsIn the INDUSI system, 500 hertz, 1000 hertz and 2000 hertz circuits are used.The 2000 hertz magnet is placed at a main signal, the 1000 hertz magnet is at adistant signal and the 500 hertz magnet at a distance of 450 meters before the pointof danger, which in general is at the end of the overlap.13
Positioning of Indusi magnetsIn the traditional INDUSI system, supervision was based on speed supervisionwhen passing the magnets or fixed times after that occurrence. In the newer trainborn equipment which is based on micro-processor technology, a continuoussupervision of braking curves which is triggered when passing a magnet is performedby the software logic.Transmission Based Intermittent Systems.A common feature of the intermittent systems described previously is their ratherlimited “data transmission capacity”, usually equivalent to 1 bit of information (signalon or off).Modern intermittent systems are based on transmission of data-telegrams totrains. These telegrams are always secured by a safety code, so that sporadicinterference cannot cause an undetected corruption of the message. Existingsystems are either based on transponders with a contact length for data transmissionof less than 1 meter or on loops which can have lengths of up to a few hundredmeters.A typical representative of the transponder solution is the KVB system used bySNCF, which in turn was derived from the Swedish Ebicab system. A minimum of twotransponders is laid out in the middle between the two rails. The duplication of thetransponders primarily guarantees the safety of the system and also enables alogical detection of travel direction. The locomotive is emitting pulses of 27 MHzcarrier frequency at a repetition rate of 50 kHz. The trackside transponder transformsthese pulses to a frequency of 4.5 MHz and reflects them to the locomotive. Theshape of the amplitude of the reflected signal indicates if a logical one or a logicalzero is transmitted. This system needs no trackside power supply for thetransmission itself and hence no cabling if the information in the transponder orbalise is fixed. Active transponders and/or transponders transmitting variable dataobviously do need to be cabled.A further development of the transmission principle of Ebicab and KVB is appliedin the ERTMS/ETCS Eurobalise.14
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: AWS MagnetsAn electrical transmissi
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 and 24: fairly rare occurrence and, when th
Page 25 and 26: Examplesof ATP/ATC systemsLZB As Ex
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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