THE European Union’s Technical Specification for Interoperability covering control-command and signalling subsystems (CCS TSI) has been recast, with the previous version that came into force in 2016 now repealed.
“We have produced a brand-new text to replace the previous one,” says Mr Juan Hernández, project officer at the ERTMS unit of the European Union Agency for Railways (ERA). “It is a framework to manage specification changes. It is an attempt to have far better alignment between products and specifications and, at the end of the day, better interoperability and safety.”
Hernández points out that up to now ERTMS projects or deployments have largely been country-based, with very few cross-border projects. “But if the European deployment plan progresses as expected, in 10, 15 years’ time we will have a denser and more connected network,” he says. “The basic aim of this TSI recast is to be prepared for those scenarios where we have more real cross-border operations.”
“In the past you could have tailor-made or customised compatibility of your onboard equipment with a specific network. But now, if your train is running through France, Belgium, the Netherlands and Germany, you cannot have your onboard equipment tailor-made for all of them. We have to make it Europe-wide.”
The recast CCS TSI came into force on September 28 2023 as part of the TSI revision package completed by ERA last year. To support the European ERTMS deployment plan, more robust management of the CCS TSI is required, says Hernández, and the recast has included improving the process for correcting errors.
As Regulation (EU) 2023/1695 implementing the new CCS TSI states, ERTMS is a complex software-based system requiring active specification maintenance, and in its capacity as ERTMS system authority ERA has now specified the procedure for correcting errors in CCS subsystems and the successive versions of ETCS.
“The process for finding and resolving errors mostly remains unchanged, but we have put the focus on analysis and correction,” Hernández says. Formal analysis must be undertaken by all stakeholders. In the case of ETCS and GSM-R, where functionality is mostly trackside-driven, this would start with the infrastructure manager. “What is mandatory is to conduct this analysis following the steps defined in the TSI,” Hernández says. “If it turns out that an error may occur that impacts normal service, then the TSI also requires this to be fixed, which is common sense but until now was voluntary. We now have more structure and mandatory steps to perform.”
These changes were discussed extensively with the rail sector during the recast of the CCS TSI, Hernández reports, noting that they will require increased effort on the part of suppliers. “We have set it down on paper and it will take some time before we see the actual benefits and the actual feedback from experience.”
Mandatory specifications
The recast CCS TSI also takes a new approach by providing only one set of specifications. Appendix A sets out in Table A2 the list of mandatory specifications for ETCS Baseline 4 Release 1 and for other ERTMS components, including GSM-R Baseline 1 Maintenance Release 1 as the current Railway Mobile Radio (RMR) system providing track-to-train communications. Baseline 0 of GSM-R’s future replacement, FRMCS, appears for the first time in the CCS TSI here, as well as ATO Baseline 1 Release 1. As Hernández explains, this set replaces three previous versions: Set 1 containing the specifications for ETCS Baseline 2; Set 2 which was Baseline 3 Maintenance Release 1; and Set 3 for Baseline 3 Release 2. “Each of these different sets of specifications had a different level of functionality, but also different levels of error correction,” he says. “Sets 1 and 2 had known errors that were only fixed in Set 3.”
Baseline 4 Release 1 is intended to provide as far as possible an error-free set of specifications for ETCS. It also provides for correcting errors without the need to adopt functionality that a project or business may not require. “You can have the error corrections without being forced to go to the latest functionality,” Hernández says. “Because as ETCS is developed, we are always adding new functions on top, we are increasing complexity.”
In contrast with the previous TSI, which contained a partial fulfilment option not to implement all functionality on the basis of reasoned argument, the recast CCS TSI has reduced the scope for not implementing its provisions in full. “If you define a vehicle that only has the specific functionality for a section of the network, that made sense in the past because the technology was not mature enough and it was a major effort to develop the full functionality,” Hernández says.
“This results in project-specific interoperability. But the objective for interoperability in Europe is to have a vehicle that can run all over the European network.”
Nevertheless, Hernández emphasises the change introduces a “transition phase” rather than cancelling this completely. “The idea is that we need to get products closer to the specification, and this is not only by making products that are compliant, but also, as in some cases that were highlighted by the sector, by tackling specifications that are too high and are somehow over-specified,” he says.
“We are ready to simplify or remove them, but we need to do it formally, not just because something was over-specified and the supplier or the project are able to skip it due to partial fulfilment. We need to make it transparent, so if something is not correctly specified, we create a change request, we modify the specifications and we put it to the right level.”
Mr Jo De Bosschere, head of the ERTMS unit at ERA, adds: “If we can arrive at products, especially for onboard, that are implementing all functionalities and are very close to the specifications, then we should automatically have better interoperability between onboard and trackside.”
Deployment requirements
The stronger deployment requirements included in the recast CCS TSI reflect the desire of the European Commission (EC) to achieve a more extensive rollout of ERTMS across Europe’s rail network. “They undertook a cost:benefit analysis and the conclusion was that the overall business case for European deployment has more benefits if we have stronger deployment from the beginning,” Hernández says. “This additional effort at the beginning will pay off at the end.”
The recast text says that in order to be placed on the market, “new vehicles shall be equipped and ready for operation with ETCS.” Under the previous CCS TSI, this requirement did not apply to mobile infrastructure construction and maintenance equipment, shunting locomotives, and other new vehicles not intended for operation on high-speed lines. Exemptions also applied to rolling stock intended exclusively for national service outside the corridors defined by the 2012 version of the CCS TSI, and not operating on lines connecting with the main European ports, marshalling yards, freight terminals and freight transport areas. Vehicles operating on cross-border lines that did not form part of Trans-European Transport Network (TEN-T) were also exempt.
The basic aim of this TSI recast is to be prepared for those scenarios where we have more real cross-border operations.
Juan Hernández, project officer at the ERTMS unit of the European Union Agency for Railways (ERA)
Under the heading of national requirements, the recast CCS TSI now says that EU member states may decide to exclude on-track machines including road-rail vehicles from the obligation to equip them with ETCS, RMR or ATO in a specific area of use if their operation does not prevent the decommissioning of national legacy Class B train protection systems. Exemptions may also be granted for passenger trains reserved for strictly local use, and shunting locomotives in service for more than 20 years that operate exclusively on a part of the national network where there is no ETCS at present and no deployment is planned for the next five years.
“For each of the new requirements of the new TSI, there are dates given for when you need to comply with them, such as installing ETCS, which is one of the main elements,” Hernández says. “We are allowing some time to adjust to this.” An appendix setting out the timescale for compliance and the transition regime has been created for each TSI, following a common approach developed by a transition and migration working group at ERA.
“This does not mean that if you are producing vehicles from September 28 2023 you already need to equip them with ETCS,” Hernández says. “We allow some time to do this, usually between three and seven years. The standard transition period is seven years, which means that seven years after the entry into force of the TSI, all vehicles should be compliant. But there are steps and an approach to enable this transition. That gives predictability.”
The transition regime for the CCS onboard subsystem is set out in Appendix B of the recast TSI. For ETCS onboard implementation, the requirement to fit all new vehicles applies immediately where the design phase has not started, and from January 1 2026 for special vehicles. If design is already underway, the requirement applies from January 1 2028, and from January 1 2030 for special vehicles. For new vehicles in the production phase, the requirement to fit ETCS applies from January 1 2030. Existing vehicles should be equipped and ready for operation with ETCS as the Class A train protection system if any new Class B system is installed within the CCS onboard subsystem.
“We have also introduced notification periods for when an infrastructure manager wants to deploy new functionality such as ATO, and we are also prepared for FRMCS,” says Hernández. “The infrastructure manager will in principle indicate through the European register of infrastructure (RINF) at least five years in advance that they intend to deploy new functionality, so that vehicle owners and operators can be prepared. Shorter periods are allowed, but with the agreement of all stakeholders.”
New system versions
Under Baseline 4, three new system versions of ETCS have been introduced to accommodate the transition to new functionalities, such as ATO up to Grade of Automation 2 (GoA2), and ETCS readiness for FRMCS and the Digital Automatic Coupler (DAC). Fully backwards-compatible with previous lower-numbered versions, version 2.2 includes ATO at GoA2 as an option, while the new version 3.0 is not backwards-compatible as it contains trackside changes that will also require onboard modification, such as fitting FRMCS equipment as GSM-R is replaced. Other new functionality in 3.0 that is also included is “supervised manoeuvres,” the ability to perform shunting without lineside shunting signals through deployment of the DAC system, which provides train integrity, and monitors whether the train remains complete from head to tail.
As Hernández points out, ATO is not mandatory, but would enable train performance to be enhanced through automatic operation when both infrastructure and vehicles meet the version 2.2 specification, while retaining the capability for manual driving.
“All the other enhancements are moved to version 3.0, which means that in order to operate on 3.0 infrastructure, the operator is required to have a 3.0-equipped train, they will need to upgrade or migrate all their fleet to this,” he says. “One of the key elements of version 3.0 will be FRMCS. As FRMCS is not yet available, then infrastructure managers cannot yet require it since the onboard products are not yet available.”
For the trackside, Hernández says a special version, 2.3, has been created to allow the use of FRMCS and DAC when available, but without removing backwards-compatibility. “If you deploy version 2.3 trackside, it can be operated by 2.2 or previous versions but also by 3.0 vehicles,” he says. Version 2.3 includes both GSM-R and FRMCS, allowing for migration from one to the other, as well as retaining lineside shunting signals.
The rail system needs to reduce costs, and costs can be reduced by standardisation, meaning adherence to the TSI.
Josef Doppelbauer, ERA executive director
Recasting the CCS TSI has also seen the merging of ETCS Level 3 with Level 2, including complete train integrity specifications. “It’s the first time we have the specifications ready with all the elements to operate at what was the former Level 3,” says Hernández. “Now you have Level 2 without train integrity and Level 2 with train integrity. This is simplified because for the operating rules for the driver, there was almost no difference between operating in Level 2 and Level 3.
“On the trackside, it simplifies the engineering rules a great deal and removes the need for additional transition between Level 2 and Level 3,” he says. “It also opens the door to hybrid operation where you have on the same track trains that rely on trackside train detection and other trains that are equipped with train integrity. This was also a technical achievement.”
Train integrity without the use of trackside train detection systems, such as track circuits or axle-counters, was only previously possible under the now-merged Level 3, and was based on trains reporting their position and train integrity information to radio block centres (RBCs).
Hybrid operation allows some flexibility, “because you can have trains that are fitted with train integrity, which have higher performance because they know where they are, or if trains are not equipped with this the trackside will still need some train detection assets,” Hernández says.
“It’s not as cheap as pure train integrity, but on the other hand you can accommodate all the performance traits of those trains without train integrity. This is a compromise between going to the highest level of performance, which is trackside without train detection systems, and requires all trains to be equipped.”
“For train detection compatibility, we have agreement with the sector and we have a target system defined,” Hernández continues. “This means there are no longer open points in the CCS TSI related to train detection and now we are starting our analysis work for migration. We know the type of system that we want, so we are asking the sector to provide us with the characteristics of non-TSI compliant systems, the ones that are installed today but are not part of the target system.
“We are getting this information from all infrastructure managers and all member states, and with that information we will create specific cases. When we have the specific cases the EC will define the migration path towards the target system.”
National implementation
Member states are required to provide an overview of where and when they expect to deploy ERTMS and to place into service a TSI-compliant train detection system over the next 20 years, as well as detailed information on the schedule for cross-border lines and key network nodes. This is part of their obligation under section 7.4.4 to produce by June 15 a national plan for implementing the recast CCS TSI.
As De Bosschere points out, this is not the first time that member states have been required to produce a National Implementation Plan (NIP), “but it’s the first time that there’s a really major focus on it and that a complete template has been provided,” running to 32 pages and contained in Appendix H of the CCS TSI. “You cannot submit whatever you want, the aim is to have structured information so it can easily be put together to provide an overview of deployment across Europe,” he says.
As well as providing information on the current status of Class A and Class B systems, member states are required to set out their technical migration strategy for ETCS, radio, ATO and onboard CCS subsystems, as well as dates for placing into service ETCS and FRMCS, and when Class B train protection systems and GSM-R will be decommissioned. “The aim here is that the member state also has a role in coordinating between the infrastructure manager and the operators to see when ETCS will be introduced on which lines, which baseline will be chosen and when FRMCS will be introduced,” De Bosschere says. The data provided will inform an update of the European ERTMS Deployment Plan.
“We want to have a complete overview of what is and what is not compliant, and then a possible migration plan for what is not compliant,” De Bosschere adds. “It’s quite a change and also I think quite a challenge for the member states to produce.”
By providing the technical foundations for what is hoped to be a faster and more widespread deployment of ERTMS across Europe, the recast CCS TSI should help the EU meet its environmental targets by improving interoperability and reducing the cost and operational complexity of cross-border operations.
“The name of the game is the decarbonisation of the transport system and this also means modal shift to rail,” says ERA executive director, Mr Josef Doppelbauer. “In order to have this modal shift, we cannot force people to use rail; the railway system must become more attractive. To be attractive, the rail system needs to reduce costs, and costs can be reduced by standardisation, meaning adherence to the TSI.
“The highest potential for modal shift in rail is in cross-border transport and here the TSI package comes into play and here we most dramatically see its impact,” Doppelbauer continues. “In relation to ERTMS, this means we need the possibility of operating with a single onboard unit on our vehicles. To have ETCS where we can have full technical interoperability. If we have reduced costs, investment in infrastructure and the removal of technical and operational barriers, we can have a greater modal share for rail and a decarbonised transport system.”
