ETCS Level 2 compared: What sets national implementations apart
Although the European Train Control System Level 2 (ETCS L2) is regarded as the European standard, its implementation varies considerably from country to country. A research project carried out by TU Dresden in collaboration with DB InfraGO AG highlights the different approaches and technical solutions adopted in ETCS implementations and identifies areas where there is potential for greater harmonisation.
ETCS is regarded as a standardised train control system for interoperable European rail transport. From the outset, the aim of the train control system was to create a common European technical standard that would, at the same time, offer sufficient flexibility to take account of national operating procedures and infrastructure conditions. However, this flexibility has led to implementations in individual countries differing, in some cases, significantly.
As part of a Master’s thesis, TU Dresden, in collaboration with DB InfraGO AG, analysed the differences between selected national ETCS Level 2 implementations. The focus is on selected operational scenarios, including the ‘Start of Mission’ (SoM) – that is, the start-up of a train before the journey begins – as well as shunting movements in stations.
Different paths to the same goal
The analysis shows that infrastructure managers in Europe pursue different strategies to meet the same operational and safety-related requirements. Reasons for this include national safety philosophies, existing infrastructure and different signalling and signal box systems.
This is particularly evident in the SoM process. Before a train is granted permission to run, several conditions must be met: the route must be defined, the train’s position must be clearly known to the Radio Block Centre (RBC), and the section of track ahead of the train must be clear. National solutions vary considerably in this respect.
Trusted Areas or maximum flexibility?
A key difference lies in the handling of so-called ‘Trusted Areas’ (TA). These are defined sections of track within which the vehicle’s position is considered to be unambiguous and reliable. Railway infrastructure managers such as the Austrian Federal Railways (ÖBB) and DB InfraGO AG design TAs. The German concept thus makes it possible, under certain conditions, to grant trains a running authorisation in ‘Full Supervision’ mode whilst they are stationary.
Other operators, such as the Swiss Federal Railways (SBB) or, to some extent, the Czech railway infrastructure operator Správa železnic, do not use this concept. In these cases, the train only receives its unambiguous position determination after passing over the relevant balise groups.
The study highlights a clear difference between the approaches: whilst Trusted Areas enable faster operational processes and shorter route occupancy times, they require more balises and involve greater planning effort. Implementations without Trusted Areas, on the other hand, are simpler in structure but incorporate the human factor more heavily into operational processes.
DB InfraGO AG prioritises technical safeguards
A distinctive feature of the German ETCS implementation is the ‘SR authorisation with balise list’ function developed by DB InfraGO. It serves to safeguard the SoM procedure at the fallback level. This ensures that the SR authorisation is sent to the train actually intended. This reduces operational risks and, in many cases, eliminates the need for written instructions for the start-up procedure.
Harmonisation as the next step
The findings of the study make it clear that, although ETCS is based on a common European standard, there are still significant variations between national implementations. At the same time, new technologies offer opportunities to reduce existing differences and pave the way for greater harmonisation. Ongoing research at TU Dresden is examining how ETCS can be further standardised across Europe in future and, in particular, simplified in Germany.
Anyone wishing to explore the results in greater depth can find the full comparative analysis in the academic article from the journal SIGNAL+DRAHT, linked here.
