The importance of migration from GSM-R to FRMCS

The European Green Deal announced recently by the European Commission’s President, Ursula von der Leyen, has the ambition to make Europe the first climate neutral continent by 2050. Within this context, the European Rail Infrastructure Managers association (the EIM) and its members envisage that significant opportunities will be offered by the new EU objectives and forthcoming policies to promote rail as the greener mode of transport for both passengers and freight.

To support the European Green Deal, railway undertakings and infrastructure managers will have to extend the rail network and run more trains to accommodate passenger growth, even doubling the number of travellers compared to previous years in some countries. High-end connectivity, digitalisation and interoperability will be key components in meeting these ambitious goals.

FRMCS to empower the industry

The Future Railway Mobile Communication System (FRMCS), the successor of the Global System for Mobile Communications – Railway (GSM-R), is expected to be rolled out in the coming years and should empower the railway industry to better leverage the potential given by modern communication technology.

In fact, the European Union Agency for Railways (ERA) has identified FRMCS as one of the ‘game changers’ in its European Rail Traffic Management System (ERTMS) Longer Term Perspective document. The Control-Command and Signalling Technical Specifications for Interoperability (TSI CCS), which is expected to be complete by 2022, will incorporate the FRMCS as the radio system to be used for train‑to‑track voice communications and for European Train Control System (ETCS) data communication.

The importance of preparing migration on time

While work is progressing well on the functional and technical specifications of FMRCS, it is essential to address, at the same time, key elements for a successful migration from GSM-R to FRMCS which involves many different stakeholders of the railway community and, therefore, requires long-term planning.

The EIM and its members have identified the following key principles for a successful migration:

1. Migration of trains to support FRMCS prior to the infrastructure’s migration (as there will be a transition period when both GSM-R and FRMCS are simultaneously operated across the railway network)
2. A sufficiently long period (e.g. five years) granted by the infrastructure manager regarding the implementation of FRMCS. It is important to decommission GSM-R to give flexibility to railway undertakings to adopt the new communication technology
3. An early standardisation of the architectural framework and interfaces of the on‑board system, considering potential long and diverse timelines of migration and lifecycle management.

Since ERTMS and FRMCS are closely connected, the EIM and its members support the following requirements on functionality developed by the ERTMS Users Group and the International Union of Railways (UIC), in terms of on-board system architecture:

• Decoupling of ERTMS application and communication platforms, supporting an independent evolution of application and communication in terms of functionality, security and architecture. The communication platform should support upgrades without impacting the application level
• Automatic handling of network registration and handover
• Update of ETCS authentication procedures, avoiding the reauthorisation of the full ETCS application
• The on-board system supports dual mode operation (GSM-R and FRMCS)
• The on-board system encompasses a modular and flexible architecture which is future proof and requires minimal certification effort in case of modifications and enhancements
• The on-board system shall support standardised and off-the-shelf FRMCS transport services (IP message transfer), quality of service support (guaranteed delivery of messages) and bearer flexibility
• The on-board system shall support adequate measures for protection against cyber-security threats.

These requirements are applicable for new on‑board systems during the migration phase. For existing on-board ETCS, changes should be kept to a minimum, hence preserving a minimal impact on train operation and limiting costs for railway undertakings. Meanwhile, to preserve infrastructure managers’ investments, FRMCS migration should also be performed, minimising the impact on ETCS trackside constituents already in service.

Conclusion

The EIM’s proposals for a successful migration to FRMCS, are:

• The CCS TSI should support a migration strategy based on the principle of migrating the on-board system first, and then the infrastructure, i.e. dual-mode operation
• In order to facilitate migration towards FRMCS, the CCS TSI should be updated with aspecification of the ERTMS/FRMCS on-board system (reference architecture including interfaces) and network transport services required for ETCS
• To facilitate and complete the migration towards FRMCS before GSM-R becomes obsolete, the upgrade of the CSS TSI should take place in 2022. From that date onwards, vehicle owners could prepare for implementation of ERTMS/FRMCS on-board rolling stock without investment losses, while facilitating and encouraging the migration towards FRMCS
• A single reference architecture for on-board rolling stock (including standardised interfaces) is required. However, flexibility should be provided to facilitate migration of existing on-board ETCS
• FRMCS migration should be performed, taking into account the preservation of investment for both on-board and for ETCS trackside constituents already in service.