Control and safety systems take a central role in the safe operation of trains in European rail networks since a long time. In the early days, around 1900, the Safety of trains was ensured by the usage of mechanical interlockings. Since then, the interlocking systems have experienced a steady evolution, which resulted in the current electronic interlockings (ESTW). As a part of this evolution, also the general architecture and behavior of the interlockings evolved; while only a minimum of interaction with external systems was required in the beginning, modern electronic interlockings or operations control centers are connected to a wide variety of systems. Partly also public communication links are used for these connections.
Each new interlocking design introduced improvements to the protective functions in response to previous incidents. This continuous improvement process resulted in the situation, that railway transportation is considered one of the safest public transports. However, in recent years new challenges for the control and safety systems arose, which are the result of a change in social structures and behavior. In 1900, the greatest threats for the railway transportation were technical or human errors, this means errors that are caused from actors of the system itself. Only in rare cases errors have been caused intentionally by system-external actors.
With this recent change in social structures and behavior, it had to be observed, that the railway is attacked more and more by external actors. These types of deliberate attacks on control and safety systems have only be considered in a certain extent yet. Due to the increasing amount of such attacks and the potential degree of damage, which may be caused by such an attack, these are no longer negligible and must be treated properly to achieve adequate protection.
This topic gets even more important considering the current developments in industrial automation and transportation systems which aim at improving the performance to remain competitive to other means of transport. This is mostly achieved by digitalization of those systems, which in general means that the formerly isolated systems are now highly interconnected and use standardized protocols on COTS components. To ensure that these systems always operate safe and humans are not in danger security has to be ensured.
Solutions how to enable digitalization can be found within the results of the CIPSEC project.
Christian Schlehuber (Deutsche Bahn)