Technical interoperability is at the core of virtually any reform of the EU railway sector. To create the single European railway area with smooth cross-border train operations, the EU decided to impose harmonisation of technical interfaces and subsystems in the form of technical specifications for Interoperability.
The first such Directive was adopted in 1996 with 1996/48/EC on the interoperability of the trans-European high-speed rail system. This was accompanied 5 years later by Directive 2001/16/EC on the interoperability of the trans-European conventional rail system, both of which were then amended 3 years later by 2004/50/EC. As new amendments were introduced, in 2008 it is deemed appropriate to recast the Directives for the sake of clarity and to merge their provisions together into a single instrument with a view to simplification. This resulted in Directive 2008/57/EC on the interoperability of the rail system within the Community. Further minor amendments to 2008/57/EC were made in 2009 by 2009/131/EC and 2011 by 2011/18/EU.
⇒ With each Directive, the EU extended the scope of interoperability and strengthened the interlinking and technical harmonisation of the national rail networks with the aim of establishing an area without internal frontiers and therefore improved access and competition.