featuretrack focus
the train power supply equipment and
the train aerials. A transportable mobile is
available for temporary use on trains not
equipped with a mobile set. Such a set
will be essential for the running of steam
specials. Portables are similar to everyday
mobile telephones
GSM-R
Interoperability and Inter-
changeability Antenna at
The EU Interoperability Directive
(96/48EC) made the application of GSM-R St. Pancras.
mandatory within EU states as a bearer
for ETCS. This has meant that the suppliers countries - Italy, Germany,
had to co-operate within the EIRENE Netherlands, Norway and
project and MORANE trials to ensure that Sweden - have complete
trains equipped with any type of radio networks in place. All the
can work to any radio infrastructure, major European countries
regardless of the manufacturer. Inevitably, are committed and most
some technical problems emerged but have some operational
having the directive in place was systems. Other countries in this in open country, in congested urban
sufficient to focus minds. the world are adopting GSM-R including areas like the approaches to terminal
Inter-changeability is another matter China and India. stations, there will be insufficient
and is outside the scope of the directive. In the UK, the Strathclyde area is in trial bandwidth for every train to be
Ideally, it would be good to be able to operation, running in parallel with the connected. ETSI has prepared a case (TH
change a faulty train radio with a existing cab secure system. The Channel 102-627) for the provision of a further 2 x
replacement one from another supplier Tunnel Link has commissioned GSM-R for 3MHz in the radio band immediately
but this is not possible. Whilst the radio trackside maintenance purposes. below the present GSM-R allocation. This
performance is identical, the space Introduction into other parts of the UK will has been submitted to the EU (CEPT)
envelopes are different for each supplier begin to accelerate once performance and Frequency Management group for
and it is therefore usual to equip a operational procedures are satisfactorily consideration.
particular fleet of trains with one radio completed in Scotland. Completion should The solution is GPRS (General Packet
type. be achieved by 2012. Radio Services) which will permit packets
Better progress has been made with Use of GSM-R as a bearer for ETCS is also of data relating to movement authorities
radio infrastructure. Whilst MSC and BSC taking place. Switzerland is leading the and position updates to be given in short
products from Nortel and NSN could way with country wide commitment and bursts. Although in use on public GSM, the
always operate with each other, initially various high speed lines also use it, reliability and quality of the GPRS service
Base Stations would only work with their Rome-Naples, Paris-Strasbourg being two. is not yet trusted by Signal Engineers.
own BSC product. Since 2007, newer The Cambrian Line trial in the UK is at the 90% of the requirements are fulfilled and
versions of equipment will allow BTSs installation stage. it is hoped that the remaining 10% will
from either supplier to work with both be satisfied by the end of 2008. Another
NSN or Nortel BSCs. Constraints and the future initiative to improve data rates is EDGE
The GSM-R connection, when used for (Enhanced Data GSM Environment), which
System roll out supporting ETCS, is circuit switched and uses a different modulation technique.
GSM-R is now operational or being the connection is continuous for the Again, this is available on the public GSM
supplied in more than 20 countries and complete journey. Whilst the present service but the opportunities to improve
this will rise to 50 by 2012. Some radio frequency allocation is adequate for GSM-R performance have yet to be
investigated.
Finally, as we all know, public GSM is
slowly being usurped by UMTS (Universal
Mobile Telephone Service) offering much
better data rates for connecting mobile
telephones to the internet and other data
sources. What are the implications for
GSM-R if public GSM were to be phased
out? Firstly, this will not happen in the
short term as agreements to support GSM
exist until at least 2020.
There is a view that GSM and UMTS will
co-exist into the much longer term but
that is conjecture. It is possible that a
UMTS-R will need to be developed but
there will be other alternatives by the
time this decision has to be made. The
future, as always, is unpredictable and
surprise solutions may yet appear.
I am indebted to Les Giles, former Radio
Engineer of British Rail and Kevin Moxsom
for supply of information.
38 | the rail engineer | october 2008
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48