G. Di Mambro Italian State Railway - Research and Development Sector of Inj?astructure Company (R. F.0
Abstract Starting from the ~ O ’ S , the traffic on the rails is continuously increased, as well as the speed of the involved trains: in parallel, also the management of this traffic is become day by day more difficult, imposing to install systems capable to guarantee good performances, quality and high safety level.
For each train under control, the traffic managers need to know the “specific” characteristics (service to be done, composition, weight, length, brake capability, ...) and the exact position on the line and the speed at each mo- ment: these information are necessary on a regular and continue basis but in case of circulation perturbations their availability in real time and their precision become really vital for the “rail system”.
1 Introduction During the years, all the railways have been already obliged to realise - and they are still doing it - a lot of different applications, with different philoso- phies, views, techniques .... but with the common target to reduce the “train conflict” problems, to improve the lines capability and mainly to guarantee the forecast safety level: at each moment an automatic, semi-automatic or manual system with some electric, electronic or digital devices, surveys the comfort, the security and the safety of the millions of persons that, each day, choose the train for business or tourism and to transport their goods: also in the airplane era, the rail continue to be the backbone of each integrated transport system,
The big limit of these systems is that they are based on more or less important “ground installations”, that require to realise or to improve track and track-side equipment, to install new telecommunication network and connections, in few
words “to work on the field”.. with a cost very important in terms of money and time: for this reason, an interesting challenge has been - and still is! - to find solutions at lower cost, possibly with few or no connections with the rails, but anyway able to guarantee the same performances and the same (or mo- re,. .) safety and security levels.
2 A short history of the Italian experiences In this framework, starting from 1998, many studies were carried out from the Italian Railway focalised on the GPS and GSM technology, currently available on the market:
the GPS (Global Positioning System) able to provide positioning functio- nalities for fixed and mobile applications with suitable precision and at limited cost all over the world; small and compact equipment (terminals and antennas) are available, ready for installation on rail vehicles with only few upgrading
the GSM (Global System for Mobile communications), the actual standard for mobile phones, that has been selected by the European Union as basis for the new integrated radio system for the European Railways (GSMR).
The combination of the two technologies can easily provide positioning and data collection capabilities from mobile vehicles with no need for costly ground installations along the rail lines (e.g. track-side cables and terminals, power supply, etc.), an ideal feature, considering the rail lines length. .. On this basis, two studies have been transformed in real project, carried out and tested:
1) one national (EUROSTAR), realised in ’98 and regarding the High Speed Trains, with the objective to supply real time information to:
- a control centre, for all the trains running at each moment
- the travelling passengers, for their specific train (location, next stations, actual speed and delay,. . .) to the waiting persons, for the forecast arrival time of each train in the interested stations
one international (FIRE), presented, approved and co-funded by the European Commission in 98/99, with the objective to realise the tracing and tracking of the fret wagons within the Europe; it was realised also in co-operation with some different European Railways and with Rail Customers and Fret Operators.
3 The IRIS Project On the basis of the positive results of the previous projects, in October ‘01 a new Project was launched to realise a concrete application of the previously acquired experiences.
The main purpose of IRIS (Integrated Railway Information via Satellite) is therefore to assess the ability of the proposed technologies in the framework of the Regional Trains, providing the information needed
- in very real-time for the traffic managers, by tracing and tracking in con- tinuous all the involved trains,
in postponed time for the fleet managers, by realising automatically re- ports concerning the service of each trainllocolcoach, the delays’ ave- rage, the maintenance,. . . ,
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The project is shared into two sub-projects, relating to different trial areas, where the forecast macro-functions have to be checked in the field. Each of them will be identified by a number of operations intended to achieve the objectives, within the reference sub-project, and organised in order to optimise subsequent development of the system.
The allocation of the macro functions in the sub-projects has been grouped in some successive stages, which will, as a whole, cover all operations included in the trial.
For the integrated system for traffic monitoring and for the fleet management is used a basic reproducible network infrastructure, scaling the component equipment appropriately, in officeslcentres of any size.
The overall structure turns out to be completely distributed. Access to any re- source, regardless of the sub-network and node in which it resides, will be achieved with maximum possible security without the applicant noticing it. Among other things, this permits easy integration with all other services, which the customer already has installed, in particular if these services face the Internet at the present time or in the future.
Some of the data held within the system could be made available to the exter- nal users: such users (like info displays in the stations andlor TV programs) could be provided with mimic diagrams showing the position of trains within the regional network of interest. This would be accomplished by the WEB servers providing the mimics requesting resources from the IRIS WEB server: no changes would be needed to the IRIS system apart from providing the connection and security privileges for the mimic system.
4 General architecture of IRIS The general architecture of the IRIS Project can be summarised in a very short view as shown in the following picture
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The system is based on two main equipment, one "Ground Control Station" and some "On Board Terminals" (one for train, typically installed inside the locomotive) and it uses two different technologies, the GPS (for the train loca- lisation) and the GSM (for the bi-directional communication train <=> ground)
4.1 Ground Control Station
The ground control station (fig. 3) is the heart of the system and allows the main functions: the communication management, the databases storage and the applications' running.
It consists mainly of a System server, some Client workstations and a LAN (or a WAN where necessary) to link the different units.
The system server is equipped with the necessary interfaces with the GSM net- work and also with system for data mirroring and data real time backup. The server guarantees the following features:
the management of the necessary communications with all the system components (on board terminals and workstations)
the storage and the management of the necessary databases, i.e. timetables off all the trains, file of the trains running at moment with all the received information, maps of Italian network with the relevant points (stations, switching areas, tunnels, marshalling yards, . . .) and relative latitude/longitude, access keys, passwords, . . .
the link with an Internet Service Provider to update periodically the infor- mation stored on the IRIS WEB SITE
To avoid any problems, the server is connected to the main UPS (No-inter- ruption Power Unit) of the station, capable to assure the normal operating state also without AC supply for some hours.
The Client workstations are standard PCs connected directly or via network with the server; they are normally used to display, in different ways, the fore- seen information (automatically and/or on query) ; the workstation allows also to input the controls to send to trains (change of transmission delay, on/off switching of on board sensors, modification of some on board data ...). Each workstation is equipped with a video graphic board to drive the graphics ap- plications requested by system and to display of the train trip on the conventio- nal geographic map and more on the especially built rail map ("train graph").
4.2 On Board Terminal (OBT)
The On Board Terminal (fig. 1) is the mobile equipment installed on board of the concerned locomotives. It is designed as a compact unit with suitably small physical dimensions (external layout approx. 250 x 225 x 90 mm) and with the view of reducing the on-field installation operations: its mounting can be car- ried out simply and easily, requiring no any specific workshop neither a long stop of the loco (the average of the installation time for an OBT is less than two hours...): at the end of the work, the loco equipped get immediately ope- rative. The on-board terminals are able:
to locate their position on the territory by using the GPS satellites
to monitor train conditions through diagnostic equipment, if present
to communicate with ground based information systems via the European communication standard-based GSM network.
The OBT is connected with an external GPS/GSM antenna (fig.2) and consists of five "logical blocks": a power supply unit, a CPU unit, an interface board, a GPS receiver and a GSM phone board
the power supply unit supplies the necessary power to all the other units; it is composed by two high power 24 V batteries connected in parallel, an intelligent power management board, a charge and a filter circuit: the po- wer is normally supplied from the train source (220 V AC or 24 V DC);
the CPU unit, composed by the processor and some RAM and ROM modules, manages all the functions of the OBT (positioning, data pro- cessing, communications,..);
the interface board contains sixteen gates (eight analogic and eight digi- tal), all settable as Input or Output; these gates can be used for diagnostic
purposes (internal conditioning, doors block control, shocks measu- rement,. . ,) and for future applications and implementations;
the GPS receiver is a normal market equipment for the localisation of mobiles: using the classic functions of the Global Positioning System (and in the future also of the Global Navigation Satellite System), it de- termines each two seconds the actual position of the train where it is fitted (latitude and longitude with an approximation of 20 m), the actual speed (using two following position points) and the exact time (universal time) of this determination;
the GSM phone board is also a market board with some adaptation made by the IRIS engineers; it is used to transmit the data from the train to the ground and to receive calls from the ground.
5 The IRIS running Before the train leaves from the origin, the driver puts in the OBT, using a small keyboard, just the train number: the internal processing unit “down- loads” from the database all the information concerning this specific “travel” and the system put itself in a “wait state” for new information concerning the following positions.
After receiving the train number information, the OBT - using one of the existing cable connecting the carriages - “reads” all the identifiers, stores the “train consist list” and wait to send it with the first message that is sent after the departure (read above).
During the travel the CPU verify continuously if the position sent from the GPS section “corresponds” with one of the “notable points” stored in the “travel map”: this verification is realised using a specific algorithm able to “understand” if the received co-ordinates can be assigned to a point, even if they are not exactly the same: practically each notable point is the centre of an “area” (0 50-100 m., depending on its extent: a level crossing is very different than a big station,...). When the output of this algorithm is positive, the CPU prepare a short string containing:
This message is immediately sent - using the GSM unit - as a standard sms, to the “SMS SERVER” of the telephonic service provider, who is charged to transmit it - directly if there is a connection (i.e. ISDN line) or again via sms - to the “GROUND CONTROL STATION” that receive the message normally
within 30 sec. after its sending; this unit process the message providing, with the received data:
to update in real time the traffic manager($ screen, moving the tracking trains on the line
to store in the relative databases the necessary information to produce the forecast reports, directly and/or on request, concerning the statistic of the service and the fleet management, like:
- average of delay (per day, per line, per train)
- coach service (km. really done, day by day)
- maintenance purposes (the past date, the next one, the limit,. . ..)
to send information - when it is forecast - to an Internet Service Provider; the choice of this globally-accepted and de-facto standard was made for economical and strategic reasons: the net exists everywhere and each interested person can easily access it, while a dedicate network should be difficult and expensive to realise. The access to the information is naturally protected by password and/or codes
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All the received information are however stored and kept on line for a very long period (the running year and the past one); after this, they are stored on CDs for “eternal” use, verification or inquiry.
The message is sent from the train also if the OBT is in one of the following situations:
when the setting time interval is reached and no notable points are found: it means that the train is stopped on line or something is happening (this interval is set actually at 5 min., but the value can be modified from the Control Centre in each moment)
when a request message (where are you?) is received from the Control Centre: in this case the answer can’t indicate the name of a point but it indicates only the latitude and the longitude at the answer moment
when one or more of the installed sensors indicate that the relative parame- ter (temperature, humidity, skid on curve etc.) is exceeding;
when some failures are detected (diagnostic application)
In the last two cases the message - completed with the code of the pointed alarm(s) - can be “transformed” also in a real alarm and displayed on the cockpit of the driver.
6 State of the art of the IRIS Project At present (February ‘02) the IRIS Project, after the definition of all the technical specifications of the on-board and ground equipment, has provided to built a prototype of the ground station and some prototypes of the OBT; the central station - physically located in Roma Termini station - is running as a “Pilot”, under a provisional version of the software, who is improved day by day: the full system operation will start in August ‘02 with the normal service.
The first OBT - to make on-field test - has been installed and commissioned on a train on 28 November 2001 and it is working satisfactorily until now; this train regularly ran on the Roma-Nettuno route, completing (until the end of January) 248 journeys and sending over than 4800 sms position messages.
During this test phase, also some measurements are made:
SMS position messages was measured between the Tracking Computer and the TIM GSM network: the delay average was generally in the range 10 to 30 seconds, depending on the GSM network.
the GSM signal strength was measured by the Tracking Computers at each station for each message. These measurements reveal that SMS can operate successfully even at very low signal strengths and that all stations on the interested lines are adequately covered.
The scope of the actual “Pilot” is the implementation of a suitable, significant subset of the IRIS architecture defined for the complete service, to be operated in the real environment for some months (3-6); the targets of the Pilot is the following:
to check the exact correspondence of the IRIS functions with all the needs stated in the Assessment of User Needs, in terms of effectiveness of the information provided and their satisfactory level for all the concerned actors
to test the system ’per$ormance, robustness and capability
to define and develop the hardwardsoftware modijlcations to fuljil - if possible - the needs of other interested sectors Cfret and long-distance passengers).
Some reports concerning all the features of the IRIS system should be available within this summer and, maybe, before June next: in this case, a draft of this report will be shown during the oral presentation.
