Fundamentals of train-centric train operation were developed to derive operational procedures for Moving Block and Virtual Coupling, specifically in interlocking areas. Elementary operational manoeuvres and scenarios have been developed with a formal representation at the required level of detail that extends the blocking time theory to Moving Block and Virtual Coupling. This allows a direct reference to the procedures of the UIC Capacity Code 406 for performance comparison. The X2RAIL-1 Moving Block Operational and Engineering Rules were assessed on typical operational situations using serious gaming, which identified a number of issues and recommendations. An extended functional architecture for the ETCS L3 Moving Block Trackside has been proposed with new functions and relations that improves the X2RAIL-1 Moving Block system specification.
Functional requirements for testing safety-critical systems were identified and a high-level operational concept and testing strategy for Moving Block has been derived. An extensible architecture has been developed for Moving Block system testing compatible with existing ETCS testing standards. The interfaces between the main subsystems in the architecture were defined and automated testing routines for Moving Block systems have been proposed that minimize on-site testing.
Communication technologies were identified meeting the needs of virtual coupling for low-latency direct communication. A 5G architecture in which trains maintain a cellular network connection for long-distance communication and an integrated Peer-to-Peer direct connection for short-range communication has been proposed to enable virtual coupling. A clear synergy was identified with Automated Vehicles, where 5G evolved to incorporate Peer-to-Peer sidelink communication that is already incorporated into the 3GPP standards for 5G. Other analogies that allow piggybacking on the automotive sector include enabling technologies, cooperative Intelligent Traffic Systems, and interactive traffic management, although the communication distances between trains and SIL targets are significantly greater in the Railways.
A Multi-Criteria Analysis framework was developed for assessing the impact of train-centric signalling in the operational, technological and business domains based on a SWOT analysis of Virtual Coupling for each railway market segment. Virtual Coupling and Moving Block were compared and benchmarked with fixed-block signalling on the eight criteria costs, capacity, stability, travel demand, energy consumption, safety, acceptance, and regulatory approval. A hybrid Delphi-Analytic Hierarchic Process (AHP) technique was used to weigh and combine the different criteria in final performance scores. The results showed that Virtual Coupling outperforms Moving Block on most criteria but the open safety issues of Virtual Coupling weigh heavily on the overall comparison until an equal safety maturity level will be achieved. In particular, train platooning will enable a significant increase in infrastructure capacity and operational efficiency.
The main challenges of Virtual Coupling were identified along with the required step changes to the safety, communication and control technology: interlocking, train-to-train communication, cooperative train protection and control, and integrated traffic management. Scenario-based roadmaps were developed for the various market segments based on the identified step-changes and estimated priorities, time orders, and durations. The roadmaps provide a long-term strategy for a gradual transition towards the deployment of Virtual Coupling, where system safety and performance depend on a smooth interaction of the safety and control components.
The main business risks associated with Virtual Coupling refer to late or no adoption due to poor benefit-to-cost ratios or safety concerns. Operational and commercial barriers were identified that help stakeholders in prioritising their mitigation measures to ensure timely and safe adoption of the new technology. Technical challenges and safety concerns must be resolved to give complete confidence in the system, while delivering cost-effective solutions.
