Home Rail News Finland opts for TETRA

Finland opts for TETRA

The Finnish Transport Agency (FTA) and Finnish Railways (VR Group) were one of the first to adopt the GSM-R standard for track-to-train radio based voice communication. They rolled out a nationwide network relatively quickly and duly equipped the train cabs.

The system has worked well but is now over 10 years old and much thought has been given as to a revamp or renewal strategy. Two options emerged, firstly to renew with updated GSM-R equipment or secondly to change to another type of radio network.

The decision made jointly by the Finnish Transport Agency as the infrastructure owner and VR Group, the train operating company, has been to prepare a plan for changing to TETRA – Trans European Trunked Radio Application. This comes as something of a surprise since the EU mandates that GSM-R should be the standard for main line train-borne radio in all member states. So why have the Finns chosen to change and does it matter?

No need for interoperability

The standardisation of GSM-R is all about interoperability, allowing trains to cross borders seamlessly without multiple fitment of train- borne control and communication equipment associated with earlier national system designs. However, Finland uses 1524mm (5’) track gauge, which allows through-running with Russia’s 1520mm gauge but not with the rest of Europe, so the question of interoperability with other European states does not arise.

In the early 1990s, when the decision to standardise on GSM-R was made, TETRA was still under development and was considered too risky, both technically and commercially, to adopt for international rail use. Since then, Tetra has become the de facto standard for metro rail systems and for the emergency services of fire, police and ambulance.

Recognising the need to have emergency service cover across its rail network, the Finnish authorities decided to extend their VIRVE TETRA system that became operational in 2002 to parallel the GSM-R network, thus duplicating the radio coverage to a very high percentage of route. Not all tunnels or deep cuttings are covered but this will happen over time.

The TETRA network is therefore essentially already in place and analysis has shown that there is sufficient capacity to have safety-related railway communication on the same network as emergency services, government agencies and the military.

There are three main factors in reaching this decision.

Significant savings can be made, estimated to be €10 million per year. This seems a lot of money but two very high costs can be avoided. Firstly, the GSM-R operation, including the provision of base stations and masts, is provided by a private company. The subscriber fees are much higher than those for the TETRA network. Secondly, the GSM-R network is largely reliant on rented or leased lines to connect its base stations back to the signalling control centres and the cost of these is also substantial.

In addition, the GSM-R operation has increasingly been subject to interference from 4G networks in adjacent frequency bands. This is principally by telecom service providers who are seeking to achieve maximum coverage of their networks and who have adjusted their base stations to give maximum allowed transmission levels so causing disturbance to the GSM-R receivers. This is a problem not confined to Finland but the solution of providing ever more sophisticated filtering equipment is complex.

Lastly, Finland has never adopted ERTMS Level 2 and thus the use of GSM-R as a bearer for the ETCS element does not arise. Mindful that ERTMS does not come about until after 2025, the Finns take the pragmatic view that ,by that time, a successor technology for GSM-R will have been decided and developed, possible ‘LTE-R’, and thus a more suitable bearer network will be built as and when needed.

Looking to the future

None of this is going to happen quickly and an EU derogation is required before the change to TETRA can be made. Since interoperability is very much a cornerstone of EU policy, this is expected to result in some difficult negotiations. The plan shows the change taking until 2018 to complete with much of this time being needed to fit out the various trains and other items of rolling stock.

The Finnish decision should not be read as a precursor to change the European main line rail network to TETRA – GSM-R is too well-established for this to happen. It does, however, highlight the need to speed up the investigative work being done on the future of GSM-R and what will eventually replace it.

The problem of unwanted interference is also something that needs to be resolved in the short term.

Another interesting element is that of outsourcing. It may be financially attractive to have a third party build and operate a radio network in the first place but the subsequent service provision costs, and especially when changes to network configuration are needed, can be astronomical. Remember the old adage “If you don’t own it, you don’t control it”.

Clive Kessell
Clive Kessellhttp://www.railengineer.co.uk
SPECIALIST AREAS Signalling and telecommunications, traffic management, digital railway Clive Kessell joined British Rail as an Engineering Student in 1961 and graduated via a thin sandwich course in Electrical Engineering from City University, London. He has been involved in railway telecommunications and signalling for his whole working life. He made telecommunications his primary expertise and became responsible for the roll out of Cab Secure Radio and the National Radio Network during the 1970s. He became Telecommunications Engineer for the Southern Region in 1979 and for all of BR in 1984. Appointed Director, Engineering of BR Telecommunications in 1990, Clive moved to Racal in 1995 with privatisation and became Director, Engineering Services for Racal Fieldforce in 1999. He left mainstream employment in 2001 but still offers consultancy services to the rail industry through Centuria Comrail Ltd. Clive has also been heavily involved with various railway industry bodies. He was President of the Institution of Railway Signal Engineers (IRSE) in 1999/2000 and Chairman of the Railway Engineers Forum (REF) from 2003 to 2007. He continues as a member of the IRSE International Technical Committee and is also a Liveryman of the Worshipful Company of Information Technologists. A chartered engineer, Clive has presented many technical papers over the past 30 years and his wide experience has allowed him to write on a wide range of topics for Rail Engineer since 2007.

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