The ERTMS (European Rail Traffic Management System) concept has been around since 1989, some 23 years ago. The idea conceived a pan-European network where trains and infrastructure would be to a common standard and rail traffic could cross borders seamlessly. So the word interoperability was invented. By now, its use should have been commonplace on all high speed lines and any other main trunk routes that have required re-signalling.

Reality is somewhat different. It is true that, in the intervening period, many lines have been equipped with either Level 1 (track to train signalling information via balises) or Level 2 (track to train signalling information via radio) but these have tended to be on discrete routes with little connection to each other. Thus the interoperability goal has yet to be fully proven and, in those areas where it has been tried, many interface problems have emerged. So why is this, and what can be done? To answer the question, one must perhaps go back in time.

Signalling and Railway Operations

Ever since railways began, different countries have invented and adopted different operating rules and signalling systems to go with them. Once embedded, these rules become part of the railway culture for a particular country and are instilled in operators and engineers alike. So strong is this that trying to instigate change is an uphill struggle. The temptation when new technology arrives is to adapt the technology to fit the rules rather than change the rules to fit the technology. Since, in real terms, no railway (at least within Europe) can claim that its rules have led to a dramatic improvement in operational efficiency and safety over any other railway, the need for the differences is questionable.

Thus operating and signalling have become prisoners of history and the ERTMS concept has battled since its inception to overcome these long established traditions. To try and get greater uniformity of thought and action, the ERTMS Users Group was established in 1995. It has a published mission statement: “To help the railways in applying ERTMS/ETCS in a harmonised and interoperable way to enable the free flow of trains and a competitive railway”. Located in Brussels, I met with Michel Ruesen, its Managing Director, and Hugh Rochford, one of its senior engineers who is also the secretary to the IRSE International Technical Committee, to find out what the current position is and their predictions for the future.

Forcing the Standard

The European Union holds the aces for ongoing ERTMS development and extension since it is one of the prime sources of finance. Six pilot projects were originally set up to prove the ERTMS safety and interoperability concept, but with the condition that collective joint responsibility would be taken by the participating railway organisations. The first three were in Germany (DB), France (SNCF, succeeded by RFF) and Italy (FS, succeeded by RFI), followed on by two in the Netherlands (NS Railinfrabeheer and succeeded by ProRail) and Spain (RENFE, succeeded by ADIF). Thus the Users Group was created as a European Economic Interest Group (EEIG ERTMS Users Group).

Membership is now extended with the UK (Network Rail), Switzerland (SBB), Sweden (Trafikverket) and Denmark (Banedanmark) having joined, and comprises almost all European countries operating substantial ERTMS systems. Not to be involved means having no influence on the progressing of standards. Further, the knowledge base in individual countries is somewhat sparse so a collective approach is accepted as the optimum means of maximising expertise.

The ERTMS Users Group goals are to ensure a free flow of information on the technology whilst recognising that competitive tendering must take place for the supply of both infrastructure and train borne equipment. The focus is on two of the three elements of the ERTMS package – ETCS, the signalling system, and GSM-R, using radio for data transmission. The third element is ETML, the traffic management layer, but this has made little progress to date.

Influencing the specifications is a prime responsibility but going hand in hand with this is monitoring project implementation and testing. The task of controlling additional functionality is important but also vital is the need to ensure backwards compatibility by making sure that new generation ERTMS fitted trains can run on existing ERTMS tracks, thereby protecting the investment already made in the infrastructure.

The ERTMS Users Group is recognised as the Knowledge Centre for ERTMS and this includes the expertise in the handling of ERTMS studies funded by TEN-T (the Trans-European Transport Network).

How the ERTMS Users Group works

The Group combines the knowledge of around 60 experts, of which 10 are located at the central office in Brussels. The other 50 are dotted around the railways, including engineers from Network Rail. Several management and technical meetings are held every month between the member organisations, using English as the universal language, covering topics such as change requests, driver-machine interface, key-management, engineering rules and testing/validation.

The Group has close liaison with other European sector organisations, these being:

• The European Commission (DG-Mobility) and the European ERTMS Co-ordinator

• ERA, the European Railway Agency

• The TEN-T Executive Agency, co-ordinating all TEN-T financed projects

• CER, the Community of European Railways

• EIM representing the independent European Infrastructure Managers

• ERFA, the European Rail Freight Association

• UNISIG and UNIFE representing the equipment suppliers

• GSM-R Industry Group, representing the GSM-R suppliers

• Rail Freight Corridors 1/A (Rotterdam/Antwerp) –- Genoa, 2/C (Antwerp/Rotterdam) –- Lyon) and 6/D (Valencia – Budapest)

• UIC, the international organisation of railways.

The ERTMS Users Group is essentially an advisory body and has no enforcement powers. This latter has to come from legislation passed by the EU using the ERA as its agent. More than €200 million of subsidy has been allocated to the Group since its inception.

Technical Standards of Interoperability

EU legislation has been in place for some time to mandate ERTMS for high speed lines. Under the project to create European Rail Corridors, the TEN-T concept, it was logical to make these ERTMS equipped throughout, thus aiming for a seamless control system. This is now extended to the international freight traffic, recognised by six so called ERTMS Corridors as part of the European Rail Freight Corridors.

More recently, the same mandate applies to other trunk rail routes when the time comes for these to be re-equipped with a new control system. Existing ATP technology may only be used in the short term providing this does not constitute any enhancement to the national ATP system. It is expected that regional lines will be included in the legislation before too long although some adaptation of the standards has to be finalised before this can happen.

Ongoing Challenges and the Future

The Users Group has the task of facilitating the provision of a universal train control and communication system in place across Europe. This must concentrate initially on getting all present ERTMS systems operating to the same specification such that regardless of who supplies the equipment, it will work across all networks. The challenge is considerable as there are many variables that make for a successful ERTMS operation and which must be made to harmonise with each other. Examples are:

• Harmonised operating rules

• Harmonised signalling rules

• Common specification for infrastructure equipment and deployment

• Common specification for train borne equipment

• Common radio-on-air interface

• A software level that allows all operating and signalling requirements

• Commonality of approach from infrastructure providers

• Commonality of approach from train borne equipment suppliers.


As has been seen, many of these are rooted in history and it will take a lot of persuasion to get change. Others relate to technology. Getting a robust and recognised software level was always going to be difficult as ERTMS had to be developed with many upgrades to software along the way. Version 2.3.0d is currently the standard, but this was reached with high speed rail operation in mind and all the safety requirements that go with that. As the UK has witnessed on the Cambrian, it is over restrictive for operations on regional lines and thus baseline 3 will shortly be introduced as the standard that will be acceptable for all operations across Europe. However, it will have to be backward compatible with 2.3.0d as the logistics of upgrading all existing trackside equipment to baseline 3 over even a short period of time are impossible.

An issue in the short term is the situation in Germany where existing ATP systems are still fairly new and a large replacement programme is not yet needed. Since Germany is a big country in the middle of Europe, not having ERTMS will impact on several corridors, the main ones being Prague / Vienna to Warsaw, and Rotterdam to Switzerland and Genoa. A solution for these international freight corridors, where Germany committed itself in the past to enable foreign freight ERTMS-equipped trains to run on them, is being sought.

GSM-R is another longer term problem. With the GSM standard (2G) for public mobile radio now largely replaced by 3G, and with 4G not far off being launched, the future for GSM-R has to be considered since its data handling capacity is limited and the availability of products will not be safeguarded. Michel Ruesen is of the view that the future radio element of the specification will concentrate on application rather than technology. This should allow normal technological advancements to be made without having to universally change the radio hardware

The enthusiasm and expertise of the team is impressive, and so it needs to be as the challenges for the future are significant. The technical elements are hard enough, but getting a mind-set change amongst the individual railways will be equally difficult. We must all wish them well.