Interoperability Directive (2016/797)
Directive (EU) 2016/797 sets the conditions under which railway vehicles and fixed installations are designed, built, authorised and placed on the market in the EU. It is the legal foundation for the Technical Specifications for Interoperability and for the single vehicle authorisation issued by ERA.
The Interoperability Directive of 11 May 2016 recasts Directive 2008/57/EC and forms the technical pillar of the 4th Railway Package together with the Railway Safety Directive and the ERA Regulation. Member states had to transpose it by 16 June 2019, with extension options that ran to 31 October 2020.
The directive defines the structural subsystems — infrastructure, energy, trackside and on-board control-command and signalling, rolling stock — and the functional subsystems of operation, maintenance and telematics. Each must meet six essential requirements: safety, reliability and availability, health, environmental protection, technical compatibility and accessibility.
The TSIs translate those essential requirements into concrete technical specifications, one TSI per subsystem. The directive is thus the constitutional layer; the TSIs are its operative law.
One authorisation instead of many
Under the previous regime, a vehicle intended for several countries needed a separate authorisation in each. Since June 2019, a single vehicle authorisation issued by ERA covers the whole intended area of use across member states, applied for through the One-Stop Shop.
For vehicles used in one country only, the applicant chooses between ERA and the national safety authority. Conformity with the TSIs is assessed by a Notified Body, which issues a certificate; the applicant draws up the EC declaration of verification on that basis. Conformity with the remaining national rules is assessed separately by a Designated Body, which issues its own verification certificate on that different legal basis.
Authorised vehicle types are registered in ERATV, the European register of authorised vehicle types, while the network side is documented in RINF, the register of infrastructure. The practical test of interoperability is whether a train crosses a border without technical renegotiation — the directive supplies the legal machinery for exactly that.