intermittent and continuous ATP 101119 - irse.nl

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• Supervision of braking to speed restrictions imposed by track characteristics or by signalling.• Indication of line and signal information to the driver (cab signalling).Trackside EquipmentThere are three main components:• Signal Interface Unit• Loop Electronics Unit• Cable loopThe loop cable is fixed to the track by clips attached to the flange of the rail, tosleepers and by covers attached to the sleepers over each loop crossover, or loopend. The covers protect the loop from damage by people walking on the track, orfrom dragging equipment. The SELCAB track loops do not infringe the ballasttamping zone and therefore it is possible to carry out periodic track maintenance withthe loops in place.The Loop Electronics Unit (LEU) consists of two telegram generators which areindependent of each other, feeding their information through selection logic to themodulator/transmitter. Each of the two telegram generators reads the signalinformation from the six input lines. These inputs form a dual code, therefore 2 6 = 64different combinations can be defined. Each defined state selects a certain set oftelegrams.The information for selecting the correct set of telegrams is derived from thesignal aspect.Trainborne EquipmentThe onboard equipment for the Chiltern Line is based on LZB trainborneequipment for urban traffic. The processor system itself is a 2 out of 2 configuration,where the two microprocessors work independently and compare their outputs byexchange of data. In normal operation, each of the computers outputs a life signal,which is individually supervised for correct sequence of pulses by a supervisionboard. Only if both supervision boards receive proper life signals, the emergencybrake is released.Outputs to the vehicle are by means of standard industrial non vital relays. Forvital outputs, two relay contacts of different relays driven by different processors areused.Parallel input data are fed to the processors by optocouplers. Where vitaloperation is required, two independent optocouplers read the information.Operation Of The SELCAB SystemThree types of supervision are implemented:• Train trip (when passing a signal at danger)• Continuous supervision of speed• Rollback supervisionThe continuous supervision function can be split into two subtasks:• Supervision of a constant permissible speed which also is indicated to the driver. The system warnsthe driver and applies the service brake in case of no appropriate reaction.• Supervision of the braking action of the train. A number of continuous braking curves is calculatedon board which each causes a defined reaction when being exceeded.31
The first curve (indication curve) gives a brake announcement and initiates theindication of target data. The second curve (warning curve) generates an audiblealarm. The third curve (service brake curve) automatically applies the service brakewhich can only be released after the permissible speed is reached. The last curve isonly activated in case of a failure of the service brake (Emergency brake curve).This brake can only be released when the vehicle has come to a complete stop.All curves except the emergency brake curve are oriented at the position of thesignal. In case of an emergency brake application the vehicle is stopped within theoverlap. This curve points to the end of the overlap.If there is more than one target transmitted, a minimum selection for the actualposition of the vehicle is made. Up to four targets can be processed at a time.Glasgow CTS Contactless TrainstopThis description was reproduced with permission from an article in IRSE News109, November 2005 by Ed. Gerrard and David Hughes.CTS Trackside Equipment Architecture And OperationFigure one shows the CTS Trackside equipment architecture. The track beaconcomprises two polarised permanent magnets and two coils, a signal coil and afeedback coil and these coils are mutually coupled.Housed in the local Station Switchroom there is a transmitter, which is switchedon by a call for the corresponding signal to be switched to Green (DR). This sends a25.6 kHz signal to the beacon signal coil to disarm the beacon. To prove that thebeacon has been disarmed a beacon feedback coil picks up the signal and feeds itback to a detector which on receipt of this feedback signal energises a relay(CTSPR).This interfaces with conventional train stop circuitry using the VPR and VCRrelays. These proving relays then allow the trackside Signal lamp to be switched toGreen if both DR and CTSPR/VPR are energised. If the Signal is at Red then there isno transmitter signal and the Beacon is armed. In this scenario only the permanentpolarised magnets are present and both the DR and CTSPR/VPR are de-energised.32
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 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: SELCAB transmissionThe number of se
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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