HOF in ETCS

Introduction

The European Train Control System (ETCS) is an in-cab signalling system used as standard throughout Europe, and increasingly in other parts of the world. It supervises train speed and adherence to movement authorities, and is labelled a ‘Class A’ train protection system. One aim is for the system to replace the multitude of existing Class B train protection systems in use across the European Union, and thereby support interoperability of European trains across national borders.

ETCS can operate in a number of different levels and modes; Level 0 provides little or no protection and is usually used where the trackside has not been fitted with the required infrastructure. Levels 1-3 offer increasing functionality and move progressively away from traditional lineside protection. As the level type increases, the changes to system operation move from mainly affecting drivers and maintainers to also changing the tasks of the signaller. There are 17 modes of operation defined for the system, although not all railways will use all of these and some are transitory such as Stand-By mode. The main mode of operation is labelled ‘Full Supervision’ where the ETCS system provides the maximum level of supervision.

Relevance to HOF

In common with other highly automated systems, implementation of ETCS can create some HOF issues. These span usability problems with interacting with the Driver Machine Interface (DMI), problems with creating and maintaining accurate mental models of how the system works and how to work with it, as well as problems with developing appropriate competence and coordination activities between different operational roles. Migration towards full rollout of the system also poses HOF problems as it typically spans multiple years and may incorporate different system versions.

Approaches and models

In order to fill a gap, the HOFWG at UIC are developing materials and guidance on the HOF issues with ETCS that have been identified by different railway organisations. On this page, you can find information resulting from a workshop held in UIC in June 2025 where experts in HOF and ETCS assembled to share their knowledge and experience.