European Train Control System

The European Train Control System (ETCS) is a train protection system designed to replace the many incompatible systems used by European railways, and railways outside of Europe. ETCS is the signalling and control component of the European Rail Traffic Management System (ERTMS).

ETCS consists of 2 major parts:

ETCS can allow all trackside information to be passed to the driver cab, removing the need for trackside signals. This is the foundation for future automatic train operation (ATO). Trackside equipment aims to exchange information with the vehicle for safely supervising train circulation. The information exchanged between track and trains can be either continuous or intermittent according to the ERTMS/ETCS level of application and to the nature of the information itself.

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, pieces 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. The main goal of achieving interoperability had mixed success in the beginning.

The European railway network grew from separate national networks with little more in common than standard gauge. Notable differences include voltages, loading gauge, couplings, signalling and control systems. By the end of the 1980s there were 14 national standard train control systems in use across the EU, and the advent of high-speed trains showed that signalling based on lineside signals is insufficient.^{[citation needed]}

Both factors led to efforts to reduce the time and cost of cross-border traffic. On 4 and 5 December 1989, a working group including Transport Ministers resolved a master plan for a trans-European high-speed rail network, the first time that ETCS was suggested. The commission communicated the decision to the European Council, which approved the plan in its resolution of 17 December 1990. This led to a resolution on 91/440/EEC as of 29 July 1991, which mandated the creation of a requirements list for interoperability in high-speed rail transport. The rail manufacturing industry and rail network operators had agreed on creation of interoperability standards in June 1991. Until 1993, the organizational framework was created to start technical specifications that would be published as Technical Specifications for Interoperability (TSI). The mandate for TSI was resolved by 93/38/EEC. In 1995, a development plan first mentioned the creation of the European Rail Traffic Management System (ERTMS).

Because ETCS is in many parts implemented in software, some wording from software technology is used. 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).

The specification was written in 1996 in response to EU Council Directive 96/48/EC of 23 July 1996 on interoperability of the trans-European high-speed rail system. First the European Railway Research Institute was instructed to formulate the specification and about the same time the ERTMS User Group was formed from six railway operators that took over the lead role in the specification. The standardisation went on for the next two years and it was felt to be slow for some industry partners – 1998 saw the formation of Union of Signalling Industry (UNISIG), including Alstom, Ansaldo, Bombardier, Invensys, Siemens and Thales that were to take over the finalisation of the standard.