Passengers in high speed trains across Europe pay attention to the design, speed, confort and services. They may realise the growing role of a technology that is close to aeronautic standards. They may trust the train staff and the driver in particular, but usually ignore the central role of software, which is in fact controlling the whole system.
This software, distributed under the EUPL, is the open European Train Control System (OpenETCS), the signalling and control component of the European Rail Traffic Management System (ERTMS). It is kind of positive train control, replacing the many incompatible safety systems previously used by European railways. It is becoming a standard that was also adopted outside Europe and is an option for worldwide application. It is managed by the European Union Agency for Railways (ERA) and it is a legal requirement that all new, upgraded or renewed tracks and rolling stock in the European railway system should adopt it, possibly keeping legacy systems for backward compatibility
ETCS is implemented with standard trackside equipment and unified controlling equipment within the train cab. In its advanced form, all lineside information is passed to the driver wireless inside the cab, removing the need for lineside signals watched by the driver. This will give the foundation for a later to be defined automatic train operation.
The need for a system like ETCS stems from more and longer running trains resulting from economic integration of the European Union (EU) and the liberalisation of national railway markets. At the beginning of the 1990s there were some national high speed train projects supported by the EU which lacked interoperability of trains. This catalysed the Directive 1996/48 about the interoperability of high-speed trains, followed by Directive 2001/16 extending the concept of interoperability to the conventional rail system. ETCS specifications have become part of, or are referred to, the Technical Specifications for Interoperability (TSI) for (railway) control-command systems. So it is a piece of European legislation managed by the European Union Agency for Railways (ERA). It is a legal requirement that all new, upgraded or renewed tracks and rolling stock in the European railway system should adopt ETCS, possibly keeping legacy systems for backward compatibility. Many networks outside the EU have also adopted ETCS, generally for high-speed rail projects.
Because ETCS is in many parts implemented in software, some wording from software technology is occupied. Versions are called system requirements specifications (SRS). This is a bundle of documents, which may have different versioning for each document. A main version is called baseline (BL).
More information: http://openetcs.org/principles/