The ERTMS signaling system (European Railway Traffic Management System) developed by Adif and the bidirectional systems used in the Trambaix de Barcelona (Barcelona Tram), place Spain among the leading countries in railway communication technology.

Since the consolidation of the European Union, facilitating rail traffic and border crossing has been one of the main concerns of member countries. The European Railway Traffic Management System (ERTMS) was created in order to facilitate communication on EU railways.

In the last decade, Spain has become the European country with the longest ERTMS-covered stretch of network. The 1,050 kilometers of Spanish railways in service represent 37% of the total ERTMS network in the EU, both for level N1 lines (moderate rail traffic density) and level N2 lines (high rail traffic density). Further, Spain is the only country within the EU-27 in which the majority of high speed lines (AVE) also have this system. This leads to a decisive improvement in rail interoperability, reaching a technical signaling standard and safety level that can overcome differences among European countries.

The innovative ERTMS Balise Auscultation System (SABE) developed by Adif and the Institute of Applied Magnetism (IMA) from the Universidad Complutense de Madrid is also noteworthy. This SABE system receives, demodulates and decodes the messages sent from the railway, and also permits the measurement of many physical parameters from the train-balise signal, which is highly useful for maintenance and signaling. The SABE reads not only the balises already used in Spain but also those from the continuous transmission system of European balises, or Euroloop.