European Railway Agency - ERA

Making the railway system work better for society

Technical Specifications for Interoperability (TSIs)

A Technical Specification for Interoperability (TSI) is always structured as follows:

  • introduction with the technical and geographical scopes
  • definitions of the subsystem and of the scope
  • essential requirements
  • characteristics of the subsystem with particularly the functional and technical specifications of the subsystem and of the interfaces
  • interoperability constituents
  • assessment of conformity and/or suitability for use of the constituents and verification of the subsystem
  • implementation
  • appendices.

According to Interoperability Directive, a specific case means “any part of the rail system which needs special provisions in the Technical Specifications for Interoperability (TSIs), either temporary or permanent, because of geographical, topographical or urban environment constraints or those affecting compatibility with the existing system, in particular railway lines and networks isolated from the rest of the Union, the loading gauge, the track gauge or space between the tracks and vehicles strictly intended for local, regional or historical use, as well as vehicles originating from or destined for third countries”.

So a specific case needs a special provision in the TSIs, could be temporary or definitive and is necessary to face particular constraints.

Article 7 of Interoperability Directive defines the cases in which the Member States may allow the applicant not to apply one or more TSIs or parts of them.

In the former Directive 2008/57/EC, these cases were considered as a derogation while in the current wording of Directive (EU) 2016/797, it is considered as cases where TSIs do not apply.

There is no legal reference concerning the special situation, this concept has then no legal existence.

The Notified Bodies (NoBos) are responsible for assessing the conformity or suitability for use of the interoperability constituents or for appraising the ‘EC’ procedure for verification of the subsystems.

However, the TSI OPE is a special case because it does not specify any interoperability constituents.

As such, the compliance with TSI OPE is made by an assessment of the safety management system. The only way railway undertakings and infrastructure managers can demonstrate compliance with the requirements of the TSI OPE is when the relevant authority assess the safety management system before granting the safety certificate/authorisation and when they perform supervision of the railway undertakings and infrastructure managers. Therefore, a separate assessment by a NoBo is not necessary.

The Technical Specifications for Interoperability (TSIs) are mandatory. Appendices are fully part of the TSIs and so, are also mandatory (i.e. legally binding).

The European Norms (ENs) are standards developed and maintained by CEN, CENELEC and ETSI to facilitate business and remove trade barriers for industry and consumers within the EU. These organisations (CEN for instance is composed of 30 Member States) work to develop voluntary European standards. These standards have a unique status since they also are national standards in each of its Member states.

Some standards might be developed under a mandate given by the European Commission. These standards are known as ‘harmonised standards’. However, these standards are still voluntary even if they support regulations or directives but the essential requirements must be met. If a manufacturer follows the relevant harmonised EN, it benefits from a ‘presumption of conformity’ to the related essential requirement.

An EN can be specified in a Technical Specification for Interoperability (TSI). As the TSIs are mandatory, the specified EN becomes also mandatory.

The provisions set out in the Technical Specifications for Interoperability (TSIs) are mandatory (i.e. legally binding). It is then a priori impossible to deviate from them even if you regard them as not applicable. Unless there is a special provision in the TSI that sets a specific case or a deficiency is identified, the TSI shall be applied.

The scope of a Technical Specification for Interoperability is set by the Interoperability Directive.