A large number of technological hurdles still have to be cleared to achieve complete interoperability across the European rail network. This is due mainly to the historical development of country-specific train control and protection systems.

Following years of work by the railways and industry, and with support from the European Union, the first standardised European system – the European Rail Traffic Management System (ERTMS) – was developed as part of a European directive.

The breakthrough was achieved on 25th of April 2000, when the standardisation partners (all participating UIC railways, the ERTMS Users Group and the leading European rail technology companies) signed a framework agreement on the use of a standardised interoperable train control and protection system (ERTMS specifications). In autumn 2000 the member states agreed to publish these exact specifications as a committee decision, thus cementing the legal and planning process.