ERTMS stands for 'European Railway Traffic Management System'. It is a control, command, signalling and communication system. It is a software-based system for railway management and safety control. It was adopted by the European Union as a standard, allowing an interoperable rail frame in Europe. ERTMS is not the same as ETCS; ERTMS is composed of ETCS, RMR and ATO.
- ETCS (European Train Control System) is an automatic train protection system (ATP) that continuously ensures that the train does not exceed the safe speed and distance. In addition, it provides relevant information to support train drivers in their tasks.
- RMR (Railway Mobile Radio) is a dedicated radio communication system for voice and data services supporting railway operations. It comprises two radio systems: GSM-R (Global System for Mobile Communications - Railways) and FRMCS (Future Railway Mobile Communication System) that may be implemented both at the same time or each of them independently.
- ATO (Automatic Train Operation) is the system that automates the operation of the train up to Grade of Automation 2 (GoA2). The ATO GoA2 starts and stops the train automatically with ETCS providing the automatic train protection (ATP) functionality to enable the ATO functions.
ERTMS is composed of two subsystems: trackside and on-board, and in order to make it function, both the infrastructure and the train must be equipped.
The ERTMS system installed on the trackside and the ERTMS system installed on the vehicles exchange information. This information allows the ERTMS equipment installed onboard the vehicles to supervise the maximum speed allowed for operating continuously and to give the driver all the necessary information to operate with cab signalling. This includes the means to establish voice services.
ERTMS has three main components which each fulfil a different function. The basic functions of ETCS include management of the movement authorities that trackside sends to the trains, supervision of the most restrictive speed profile depending on fix/variable information.
The RMR includes voice and data services. Voice services includes functionalities as group calls, emergency calls and other railway specific applications.
The ATO starts and stops the train movement automatically, following the speed profile calculated by the ETCS, when the ATO conditions to activate the Automatic Driving are meet.
The baseline is a stable kernel in terms of system functionality, performance and other non-functional characteristics. As the ETCS has evolved over time and new functions and corrections have been added, different baselines have been defined.
“Baseline 2’’ was the first set of requirements, considered interoperable, and to be adopted at European level.
“Baseline 3” was a further development of Baseline 2 that includes additional functions and backward compatibility with Baseline 2.
“Baseline 4” is a further development of baseline 3 and encompasses the set of requirements currently included in the Technical Specifications of Interoperability (CCS TSI 2023).
The ETCS levels are defined depending on how the trackside is equipped and how the information is transmitted to the train.
Currently, there are two levels; both provide continuous supervision onboard:
- Level 1 is a spot transmission but continuous supervision onboard. The information is transmitted to the train via Eurobalise (which is a transponder deployed on the trackside and connected to the signalling equipment) only when the train antenna is on the location of the balises.
- Level 2 provides a continuous transmission of information between the train and the trackside via radio. In addition, the onboard equipment continuously supervises train movement. The train reports its position and direction of travel to the control center automatically and receives movement authorities. In this level, the Eurobalise does not need to be connected to the infrastructure with cables. It allows the complete removal of lineside signals.
The baselines include the definitions and requirements of the levels, and therefore they can be combined with each other.
Backward or baseline compatibility is independent from the level.
The specification currently includes a unique baseline for ETCS: Baseline 4. This baseline envisages the ETCS system versions that includes the functions that correspond with the previous baselines, i.e., Baseline 3 and Baseline 2.
ETCS functionality defined in the ETCS Baseline 2 is included in the ETCS system version 1. Functions added in ETCS Baseline 3 that cannot be processed by a Baseline 2 train are included in the ETCS system version 2. Functions added in ETCS Baseline 4 that cannot be processed by a Baseline 3 train are included in the ETCCS system version 3.
Non-compatibility only appears if the trackside is equipped with a higher ETCS version that the locomotive can support. In this case, due to the new functions, the locomotive is not able to run along this trackside, e.g. a train equipped with ETCS system version 2 can operate on a trackside equipped with ETCS system version 1 but cannot operate on a trackside equipped with ETCS system version 3.
The European Railway Agency (ERA), in its role as a system authority for ERTMS, establishes a transparent process to manage, with the contribution of the sector's representatives, any system changes.
ERTMS is an “enabling” technology to allow exploitation of new business opportunities, operational improvements and efficiency streamlining.
On the other hand, the promotion of international traffic requires a seamless end-to-end service. Interoperability is essential to fulfil this objective.
The main tasks of the Deployment Management Team (DMT) are 'the support of an efficient, synchronised, interoperable and timely implementation of the ERTMS deployment for each Core Network Corridor and to ensure the consistency on the network, both ERTMS trackside and on-board trains.' This can be divided into four areas, in which the DMT can make a substantial contribution:
- Closely monitoring the implementation of the work plan, to avoid a patchy implementation of ERTMS in Europe.
- Providing technical assistance to projects, aiming to remove bottlenecks and avoid inconsistent deployment of ERTMS in Europe.
- Building financial and economic methodological instruments and providing guidance to select the appropriate financing schemes according to the projects' specificities.
- Providing an online one-stop-shop on ERTMS and other information, to share common knowledge.