ERTMS: Its Rise and (Occasional) Stall
Train control systems are crucial for rail safety. The European Rail Traffic Management System has gradually been rolled out over the years, but full interoperability has yet to be realised. Discover why - and how interoperability can be brought about through shared train control systems.
The Evolution of Train Control Systems
ERTMS was envisaged to be the future of train management systems worldwide. While ERTMS implementation has seen investment and progress from countries such as China and India, in Europe itself it has been met by long delays. The 2020s will prove a crucial decade for ERTMS on the continent, with many deadlines falling within this period.
Let’s look into what ERTMS really means, and how countries across Europe have negotiated all the twists and turns of the ‘railroad’ towards a common traffic management system across the continent.
Levelling Up: An Overview of ERTMS
With the disadvantages of excessive costs and an increased risk of breakdowns, it’s little wonder that European rail has focused so much on making this a reality. But in order to understand just how ERTMS has been gradually introduced to Europe’s railways, we need to unpack exactly what ERTMS means. Despite the promise of simplicity, ERTMS is a lot more complex than that…
Firstly, ERTMS refers to the traffic management and control system as a whole and comprises two key components: GSM-R (the Global System for Mobile Communication – Rail) and the ETCS (the European Train Control System). The ETCS includes the signalling component of ERTMS, with its specific functions varying depending on the level installed on the network. This can range from a combination of onboard and lineside signalling equipment being necessary to most of said equipment being found onboard the train.
ETCS is divided into three levels. Let’s take a look at each of these:
- ETCS Level 1: The most basic level of ETCS, usually applied to an existing signalling system, which retains lineside signalling but leverages Eurobalises installed onto tracks to enable speed monitoring and Movement Authority communications onboard the train.
- ETCS Level 2: This adds GSM-R to the mix, a radio-based communications system which allows for two-way transmission of information between the train and a radio block centre, and thus eliminates the need for standard lineside signalling. However, some lineside equipment – such as train detection equipment – is still needed. Movement Authority permission is dependent on fixed blocks, as with ETCS Level 1.
- ETCS Level 3: Currently the most advanced level of ETCS, which depends wholly on radio communications between trains and the control centre and thus eliminates the need for lineside signalling and monitoring equipment altogether. In its place, train monitoring and integrity management takes place on board the train, while Movement Authority is granted on a rolling basis based on real-time track condition updates (known as a ‘moving block’). This is yet to be introduced fully due to issues surrounding the integrity of rolling stock equipped to this level (all the more important as Level 3 removes lineside equipment from the equation).
While several lines across Europe have been adapted to meet ERTMS requirements, inevitably there have been issues with its implementation. Let’s take a look at some of these difficulties and how rail networks are working to make ERTMS as liberalising and cost-efficient as possible, despite the delays…
Ways to Keep on Track
The implementation of ERTMS, and particularly its associated ETCS, continues to face problems. But fortunately, there are stop-gaps which can be put in place to minimise the costs and disruption that installing a new traffic management and control system can engender, all the while allowing trains travelling on the network to take advantage of the benefits of ETCS.
The so-called Level NTC (or National Train Control) works to ensure that ETCS can be introduced to rail networks as quickly and as cheaply as possible. This solution can be achieved in one of three ways:
- Specific Transmission Modules (STMs) – these are fitted to a train and can integrate the ETCS on board the train to the national Class B legacy train protection systems
- Bespoke interfaces – an interface can be created specifically to reformat legacy system communications into an acceptable format for ETCS
- A mixture of the two
This level is fully compatible with other ETCS levels, enabling an ETCS-equipped train to run from one level to the other without fear of a system malfunction or stoppage of any kind. Movement authority is granted by the network’s train protection system, while alerts and warnings can be displayed using onboard ETCS driver machine interface, meaning drivers can get to grips with ETCS before it’s fully implemented on the network.
While full implementation is the end goal, solutions such as this act as the first ‘sleeper’ on the track towards the full rollout of ERTMS and are especially useful in geographies like Europe where delays have been common.
Delayed, not Cancelled: Implementing ERTMS
The widespread adoption of ERTMS in Europe has met some obstacles since its inception in the mid-2000s. Yet there’s no question that ERTMS has powered on full steam ahead on certain rail networks on the continent, with some countries remodelling their implementation of the ETCS to suit their own needs and budgets.
A key concern for network operators is whether there is a cost-benefit to replacing their existing traffic management and control systems with ERTMS. The answer in most cases is yes, due to the simple fact that having one common traffic management and control system will provide cost efficiencies which operating a number of different systems won’t. Yet the timing of when ERTMS should replace these older systems is an important consideration for countries. Some, like Luxembourg, needed to replace old system anyway, and so were able to make full transition to ETCS Level 1 by the end of 2017. Other countries, like Denmark, are also keen to upgrade their existing systems to ERTMS, although they have also faced delays (in Denmark, the original deadline for nationwide implementation of 2023 has been pushed back to 2030 due to problems with installing trainborne equipment needed for ETCS Level 2).
But as with everything, there doesn’t need to be a simple black or white view of implementing/not implementing ERTMS. Germany, for instance, is due to implement a more flexible ETCS solution on some sections of its network, known as ETCS Level 1 ‘Limited Supervision’. Using this model, ETCS will only be installed at particular sections, as opposed to entire lines, of the rail network, limiting costs and increasing implementation efficiency. ‘Limited Supervision’ has also been partially adopted in Switzerland and the Netherlands, making clear the overall benefit of flexibility when carrying out ERTMS implementation.
Laying Tracks for the Future of ERTMS
The next decade will be crucial for ERTMS in Europe. Most projects currently in operation have deadlines set in the latter half of the 2020s, meaning – delays excepted – interoperability could soon become a reality on Europe’s railways.
With a combination of stop-gap solutions such as ETCS Level NTC, as well as the further testing of ETCS Level 3, the future of ERTMS in Europe looks promising. Find out more on how ERTMS compares with other traffic management and control systems in our white paper here.