Before the ERTMS was conceived, almost every single country used to have its own Automatic Train Protection System (ATP). Normally these systems were not compatible with each other and thus crossing a signalling area border meant that trains needed to implement several on-board ATP devices, each of which was self-functioning. Due to the increasing international rail services, a harmonised ATP system is needed for the European context. Thus, the aim of the ERTMS was (and is) to gradually replace the different national ATP systems in European countries.
A brief explanation of these systems, which vary significantly in terms of safety levels for safety provided for train operations, can be seen by clicking on this link:
With this status, it was already clear for the EEC in the late 1980s that the European Railway network would benefit from an interoperable standard for the European ATP. Thus, in 1989 the Commission launched a study on the issue.
By the end of 1990, the ERTMS User Group (EUG EEIG) was created with the aim of creating an initial version of functional specifications. At the beginning it only consisted of experts from infrastructure administrators, but as signalling suppliers points of view were also needed, they were also included in this group.
In 1998 UNISIG was created by the main European signalling companies, with the aim of helping to finally develop the system specifications. The first version of the System Requirement Specifications (SRS), known as Class P SRS, was delivered April 1999. With the final signature by the European Commission on ERTMS specifications (Class 1 version 2.0.0) in April 2000, the interoperability of railway control, command and signalling started working towards removing borders.
As well as the development of the technical ERTMS specifications, in 1993 the EU council issued the Interoperability Directive and a decision was taken to create a structure to define the Technical Interoperability Specifications.
In 1996, the Council unanimously decided that ERTMS should be a key part of rail interoperability in Europe and would become the standard for all high-speed lines. The EU Council Directives 96/48/EC and 1001/16/EC were developed for the interoperability of the trans-European high-speed and the conventional rail system. Subsequent decisions have created a greater commitment to ERTMS by Member States.
In 2004, the ERA (European Railway Agency) was created and designated as the ERTMS system authority, and thus is in charge of managing system specifications.
The communication between the EEC and the European Parliament and the Council on the deployment of the European rail signalling system in July 2005 is also worth mentioning.