Man, Technology and Organisation

Safety Systems for Railways

The subject area includes primarily the railway signalling systems, consisting of interlocking systems, automatic train control and centralised traffic control, and the various subsystems and components of these. The purpose of the signalling systems is primarily to ensure safe railway traffic, secondly that the railway traffic is executed in a timely and efficient manner.

Sarshar, Sizarta

Senior Scientist


IFE's work in this area includes counselling, investigation, project management, risk analysis and documentation related to the review, specification, development, approval and maintenance of a wide range of signalling systems, including the Norwegian National Rail Administration's (Jernbaneverket’s) centralised traffic control systems and various types of interlocking systems. In addition, IFE actively participates in the development and revision of international standards in the area, including the railway safety standards EN 50126 / 50128 / 50129 (RAMS).

While most existing interlocking systems are built with traditional relay technology, current installations are built as software-based systems, like for systems for automatic train control and centralised traffic control. Like many other technology areas, not least nuclear power, railways are thus in a generational change where old analogue systems are gradually replaced by modern software-based systems. This technology shift, together with the introduction of common European standards, places increasing demands on competence and change in the different railway undertakings and infrastructure managers. This is consistent with the challenges also other sectors are facing, and is an area where IFE has been working for many years.

Over the coming years, the railway sector is facing yet another generational change, represented by the implementation of ERTMS (European Rail Traffic Management System). The most visible change resulting from this implementation is that the external signals which currently are placed along the track and regulate the traffic are replaced with the transfer of signal information directly to the individual trains through the railway's own mobile network GSM-R. Moreover, the trains will be able to traffic other countries’ infrastructures, without being diversely equipped with each country's unique system for automatic train control. ERTMS can be characterized as a very large safety-critical, distributed software-based system based on common European standards. With this generational change, often characterized as the most important change since the transition from steam to electricity, railway signalling will have taken the ultimate step from being a subject deeply rooted in electrical engineering to become firmly planted in modern information and communication technology (ICT).