ETCS Level 2 without signals on branch lines: Approaches from the project work carried out by DB InfraGO and Erfurt University of Applied Sciences
How can single-train operation on branch lines – known as spur lines – be made future-proof using the European Train Control System Level 2 without signals (ETCS L2oS)? This project, carried out by students at DB InfraGO AG in collaboration with Erfurt University of Applied Sciences, analyses the technical challenges associated with this research question, presents possible solutions and offers a clear recommendation. A recent technical article presents the findings of this project and outlines possible implementation options.
As part of a joint project involving junior engineers from DB InfraGO AG and Erfurt University of Applied Sciences, technical solutions were developed and systematically evaluated for the potential migration of the branch line block – a safety system for single-train operation on low-traffic branch lines – to the European Train Control System Level 2 without signals (ETCS L2oS). The particular challenge lies in the return journey at the end of the line. This raises the question of how an ETCS movement authority can be generated and referenced when there is no virtual signal location to serve as the starting point for the Movement Authority (MA) – the movement authority in ETCS.
The aim was to identify options that would both ensure safe operation and meet the economic constraints of such routes. The project group examined several technical approaches and identified which option is best suited to future-proof operation. As part of the project work, three options were analysed in detail:
- Full configuration: Here, an additional virtual signal is projected in the interlocking and in the Radio Block Centre (RBC), which is operated by train dispatchers. Permission to return is granted via an MA generated by the RBC. This is then displayed in the driver’s cab.
- Continuous Movement Authority: Following a change in direction of travel, the vehicle receives an MA from the RBC, provided that the Start of Mission (SoM) has been successfully completed. SoM refers to the process by which a train transitions to the target operating mode ‘Full Supervision’ after being set up and the ‘Stand By’ operating mode has been activated. Fixed-data balises at the end of the line enable reliable position determination.
- Movement Authority to be requested: The MA for the return journey is not provided automatically, but must be actively requested by train drivers – for example, via a key switch on the platform. Fixed-data balises are also provided here for position determination.
The project group carried out a utility analysis that took into account technical equipment costs, operational management, and planning and approval. The result: the ‘full equipment’ approach achieved the highest utility value and is recommended as the preferred option, as it supports both safety and European interoperability. The other two approaches – the ‘continuous’ approach and the ‘on-demand’ MA – follow some way behind.
The study shows that the block section under ETCS L2oS remains technically feasible, but full equipment is considered the most future-proof solution. The ongoing digitalisation of signal box technology could further reduce infrastructure costs and facilitate implementation. The project thus provides valuable impetus for the modernisation of railway operations on secondary lines.
You can gain more in-depth insights into the project in a recent technical article (in German only) in the May issue of Eisenbahningenieur.
