2. Fundamentals of ERTMS

2.1 Use of a reference defined at European level

To have interoperable trackside and onboard equipment, it is necessary to have a common set of specifications that are sufficiently precise to guarantee that any ERTMS-equipped train can run on any track equipped to receive ERTMS trains. This is why the European "interoperability" directive (96/48) requires the use of a "subset class 1" reference for ERTMS (note 1).

It is therefore in these standards that we will find the fundamental principles of this new railway signalling system. The points described...