Proceedings 2002/2003 - IRSE

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52 SIGNALLING CONTROL CENTRES TODAY AND TOMORROW IECC uses its own real time operating system BRX (British Rail real time executive) which is specifically designed to support the networking and duplication which delivers very high system availability. To achieve predictable performance and high availability, IECC was designed around two duplicated networks, one for real time signalling data and the other for less critical information exchange. With the available technology at the time, a “register insertion ring” network architecture running at 1.5 Mbits/second was chosen, because this could achieve the required data throughput with a more predictable time response than networks based on “collision and recreate-try” strategies. Interfaces between sub-systems and network nodes are 9,600 baud or 19,200 baud serial links. As with the processor hardware, the network equipment has been very reliable, and the same supplier of network nodes has been used throughout. The only change has been that the nodes are now rack mounted cards in place of the original “black boxes”. The technology is now obsolete, and it is envisaged that at some time in the future there will be a move to a more modern technology such as Ethernet, with predictable time response achieved by installing a high speed network used at a small fraction of its theoretical capacity. One of the most recent innovations has been to move from EPROMs to CD-ROM as the means of configuring IECC sub-systems with software and data 2 . This has been made possible by using the latest processor boards with Electrically Erasable ROM memory. For security and to avoid installing additional hardware, the CD-ROM is read using a laptop PC, which is plugged directly into an Ethernet interface on the VME processor board when an update is required. This allows updates to take place much more rapidly and without physical disturbance to the IECC equipment. SIGNALLER’S WORKSTATION The VDU-based signaller’s workstation is the critical human interface on the operating floor of the control centre. The original design (SDS – signalling display system) typically incorporated four colour monitors built into a purpose-designed workstation cabinet, with a trackerball and keyboard for operator input. Normally two monitors provide an “overview” which allows the signaller to see all main running signals, points, track circuits and train descriptions simultaneously. A third monitor allows selection of a “close-up” view providing a more detailed view of selected areas, including details such as shunting signals and ground frames, and a fourth “general purpose VDU” provides a number of text areas for fault reporting and signaller interaction with train describer and ARS. High availability was provided for throughout the design, with a facility to switch any view to another monitor if one should fail, all critical functions accessible via both keyboard and trackerball, and duplicated processors with hot standby. Some of the later schemes incorporated more monitors (up to six) to allow very large areas of control. The workstations were well-accepted by signallers from the start, and there were few problems in adapting from panel working to VDUs. However, the monitors themselves and the VME graphics cards which provide the interface to the processors were amongst the first IECC components to become unavailable. The chosen solution to the problem was to replace these components with an industrial quality PC and monitor, linked to the main VME processors via a dedicated Ethernet link. This new system (DIS – Flexible Display System) has allowed much more choice in the size and style of monitors, and for many new installations and upgrades the customers now choose flat-screen monitors on a desktop, instead of the original fully enclosed cabinet. The old and new styles of workstation are shown in Figure 3. The move to a PC does not totally eliminate the obsolescence problem, as the PC components change on an almost monthly basis. A fast-track acceptance process has been specified to enable minor changes to PC specification to be tolerated without invalidating Railtrack’s product acceptance of the system. The colour VDU terminal providing the interface to the IECC maintenance technician, the IECC System Monitor (ISM), is also no longer available. This has been replaced by a PC-based system, which provides an improved Windows-based interface with some additional facilities. AUTOMATIC ROUTE SETTING The sophistication of the automatic route-setting function (ARS) of IECC is the feature which sets it apart from similar signalling control systems in the UK and overseas. Whilst automatic setting of routes for trains running in normal timetable order is commonplace, IECC uses train regulation algorithms to maintain a full automatic route setting capability during periods of service disruption, and the signaller only needs to intervene in exceptional circumstances. This contrasts with the approach seen elsewhere, such as the network management centres in Germany, where the automated system provides warning of conflicts, but the decision to change the timetabled order of trains is taken by the human not the computer. The IECC approach to automatic route setting was based on fundamental research into route setting algorithms undertaken by British Rail Research. The ideas were validated first using a system which simply provided advice to the signaller (a system called JOT at Glasgow Central in the late 1970s), and then by a full trial of ARS which took place from 1983 onwards at Three Bridges signalling control centre, controlling the Haywards Heath area of the London-Brighton line. The fully developed version of ARS was active from the first day of IECC commissioning at Liverpool Street in 1989, and immediately demonstrated its versatility in handling traffic into and out of this 18-platform terminus, despite major disruptions to service caused by initial unreliability of some of the SSI trackside equipment in a very severe EMC environment. The objectives of ARS were to reduce manning requirements in signalling control centres, and to improve punctuality by guaranteeing prompt route
SIGNALLING CONTROL CENTRES TODAY AND TOMORROW 53 Figure 3: Original and new workstations at York IECC setting when trains are running freely and optimum regulation where conflicts occur. These objectives were achieved from the start and have enabled the expansion of control centres such as York and Liverpool Street to cover very large and complex areas of railway. The system is well liked by signallers, who appreciate the automation of routine activities whilst retaining the option to take manual control of route-setting for individual trains and complete areas of railway. There is also a useful facility which allows the signaller to interrogate ARS to find out the route-setting intentions for a specific train – this can be used when it is not obvious to the signaller why ARS has delayed setting a route which is apparently available. Efficient operation of ARS is crucially dependent on the information with which it is configured. Any deficiencies will reduce the proportion of trains which can be handled automatically and increase the workload of the signallers. As with other computer based signalling systems, there needs to be a data preparation process to gather the necessary information and translate this into a form which can be used by the real-time system. The process for ARS is particularly complex as it needs to take account of traffic patterns as well as the physical disposition of track and signalling. The flexibility of the ARS algorithms means that there are
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Proceedings 2002 - 2003
Page 3 and 4: The Institution of Railway Signal E
Page 5 and 6: Contents Contents ……………
Page 7 and 8: 5 PETER STANLEY BSc CEng FIEE FIRSE
Page 9 and 10: OFFICERS AND COUNCIL 7 Photo: Colin
Page 11 and 12: 9 Institution Announcements (The pr
Page 13 and 14: INSTITUTION ANNOUNCEMENTS 11 Head O
Page 15 and 16: 13 Institution Awards PRESIDENT’S
Page 17 and 18: OBITUARIES 15 overseen the conversi
Page 19 and 20: 17 Annual Dinner and Dance The Inst
Page 21 and 22: 19 The Institution of Railway Signa
Page 23 and 24: PRESIDENTIAL ADDRESS 21 in terms of
Page 25 and 26: PRESIDENTIAL ADDRESS 23 technical l
Page 27 and 28: EUROBALISE TRANSMISSION SYSTEM, A T
Page 33 and 34: Company Announcement Bridgen Enterp
Page 35 and 36: EURORADIO AND THE RBC 33 another wh
Page 37 and 38: EURORADIO AND THE RBC 35 communicat
Page 39 and 40: EURORADIO AND THE RBC 37 PLAINTEXT
Page 41 and 42: EURORADIO AND THE RBC 39 4.7 DISCON
Page 43 and 44: EURORADIO AND THE RBC 41 would be a
Page 45 and 46: EUROCAB AND THE DRIVER MMI - AN INT
Page 51 and 52: 49 Technical Meeting of the Institu
Page 53: SIGNALLING CONTROL CENTRES TODAY AN
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Page 65 and 66: 63 Migration to ERTMS on Existing L
Page 67 and 68: MIGRATION TO ERTMS ON EXISTING LINE
Page 75 and 76: CTRL SIGNALLING AND COMMUNICATIONS
Page 87 and 88: INTERNATIONAL CONVENTION 85 RIC lev
Page 89 and 90: INTERNATIONAL CONVENTION 87 case se
Page 91 and 92: INTERNATIONAL CONVENTION 89 the sys
Page 93 and 94: INTERNATIONAL CONVENTION 91 Connect
Page 95 and 96: NINETIETH ANNUAL REPORT 93 see the
Page 97 and 98: NINETIETH ANNUAL REPORT 95 THE INST
Page 99 and 100: NINETIETH ANNUAL REPORT 97 THE INST
Page 101 and 102: NINETIETH ANNUAL REPORT 99 Accounts
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NINETIETH ANNUAL REPORT 103 Vice-Pr
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NINETIETH ANNUAL REPORT 107 Fabbian
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NINETIETH ANNUAL GENERAL MEETING 10
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112 Sydney Hosts 2002 Convention Fo
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114 SYDNEY HOSTS 2002 CONVENTION
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116 SYDNEY HOSTS 2002 CONVENTION Co
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118 Much Better Engineer Signal Eng
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120 2002 Examination Results Anothe
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THIS SPACE COULD BE WORKING FOR YOU
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124 AUSTRALASIAN SECTION dangerous
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126 AUSTRALASIAN SECTION to address
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128 CHAIRMAN’S REPORT Midland & N
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130 SCOTTISH SECTION He drew compar
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132 SOUTHERN AFRICAN SECTION at Spo
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134 WESTERN SECTION Scotland. (Atte
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136 YORK SECTION The October meetin
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138 Younger Members’ Section The
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140 The Editor would like to thank
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Railway Signalling… A Science or
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