Eurailmag - #15 - March 2007 - (Page 69)

Infrastructure dhelds can be used outdoors. Fixed GSM-R wireless alarm phones have been developed and installed along the EE HSL. This line benefits from better radio coverage than conventional lines. In fact, all High-Speed Lines are equipped for ETCS level 2, even when there are no plans to use this signalling system. Moving existing radio sites is impossible. Having to fill in coverage holes would result in a lot of additional sites, compared to plans that take into account ETCS parameters right from the start. On conventional lines, 300 km need 50 sites. On the EE HSL, which is currently an ETCS level 2 line, 58 sites have been built to cover approximately the same length. © RFF GSM-R OFFERS TRUE INTEROPERABILITY AND BOOSTS THE CIRCULATION OF TRAINS ACROSS THE WHOLE OF EUROPE Even though well defined standards (Functional and System EIRENE specifications) already exist, extra studies have been carried out to adapt GSM-R functions to the French network. This may come as a surprise considering GSM-R is defined as an interoperable system, to be used seamlessly across Europe. In fact, apart from the overthe-air interface and low level protocols of the public GSM standard, lots of functions are lacking, not properly defined or need to be improved. The biggest challenge is train location. With an analog system, the driver manually tunes in the radio channel to allow all calls to be routed to the relevant dispatcher, depending on the train location. With a GSM-R network, the traffic channel is allocated to the driver by the system, and cannot be linked to the type of train and track it is currently running on, and only depends on the serving cell. This is especially annoying when a railway emergency call is broadcast. In dense areas, it is important to alert trains on certain tracks, and those on neighbouring tracks should be advised not to stop immediately. With GSMR coverage, if in the same cell, they will all receive the same instruction, whereas with an analog network, they would have been split into two different groups, depending on the radio frequency. Creating a new and specific database, taking advantage of the existing intelligent network platform, was necessary. Wireless GSM-R track side telephone (SIEMA) Permanent availability of the GSM-R services is mandatory. As long as it is voice radio, the analog network is the reference and its requirements understood. GSM-R is equivalent to the old analog system, but the network architecture is different and so raises different issues. An analog system is regional, GSM-R is national. Given the extremely low amount of traffic and limited number of users, one switching site is sufficient. If this site suffers a major crash, GSM-R is out of order across the whole national railway network, which is another problem. Risks can be reduced, e.g., construction rules and redundancy, but not totally avoided. In France, there is one single operational switching site but a second backup, identical to the first, is also ready for service. In the case of a disaster, the recovery plan restores nominal service after a few hours, which is acceptable if this occurs only once in twenty years. When GSM-R carries ETCS level 2, availability is crucial and Quality of Service (QoS) parameters are still being studied. When GSM-R coverage for the EE HSL was designed in 2001, no one was sure what role the different components, transmission, cables, power supply and radio base stations (BTS) would play in the system’s availability. "Double coverage" is in place, but for financial reasons only, GSM-R equipment was withdrawn without building additional sites. Every radio site hosts two BTS, each connected to a different Base Station Controller (BSC) with a different optical fiber. This choice is probably not the best because most disruptions come from transmission or power supplies rather than BTS failures. Building and operating a national GSM-R network is a huge challenge. It is still a new system, and very different from a public GSM network in terms of architecture and functionalities. It's a very expensive project - capital and operational costs - but also a rewarding project, especially when international roaming can be activated, which is already the case between France and Germany. It offers true interoperability and boosts the circulation of trains across the whole of Europe Jean Cellmer, Réseau Ferré de France ERTMS: European Rail Traffic Management System: European, interoperable signalling and train control system involving GSM-R and ETCS. GSM-R: Global System for Radio Railway Communications: new European interoperable system for railway networks and train operating companies. ETCS: European Train Control System: three levels. In France, ETCS level 2 is used on new high-speed lines. EIRENE: European Integrated Railway Radio Enhanced Network: European project that defines the operating and system specifications for GSM-R. MORANE: Mobile radio for Railway Networks: following three field trials in Germany, France and Italy, this European project led to the adoption of GSM-R as the standard, European radio communications system. GSM-R site on the East European HSL A GSM-R network covers different types of lines, which will offer various services and differing levels of quality. The minimum radio level and different speeds are defined in the EIRENE specifications for train-toground radio - ETCS level 2. But it may be necessary to improve coverage, e.g., to ensure a good quality service for handhelds. In France, RFF is focusing on cell planning for cab radios only. It is estimated that ensuring train coverage for handhelds will result in 30% extra costs. However, han- EURAILmag Business & Technology Issue 15

Table of Contents for the Digital Edition of Eurailmag - #15 - March 2007

SOMMAIRE
NOTICE BOARD
COATINGS
NEWS
SERVICES
INFRASTRUCTURE
HIGH-SPEED LINES
TUNNELS
PEOPLE
ROLLING STOCK
WEBSITE DIRECTORY

Eurailmag - #15 - March 2007

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