The basic principles of interoperability

The Regulations implement the two principal elements of the rail interoperability process, as defined in the Directives. These are:

a) technical harmonisation and standardisation of the railway; and

b) common checking and authorisation processes.

The interoperability regime is linked firmly to safety.

Technical harmonisation and standardisation

The means whereby the Regulations will help deliver technical harmonisation can be summarised as follows:-

• A set of mandatory, high level "essential requirements", with which the rail system is to comply, are laid down in general terms by the Interoperability Directives;
• Neither the Directives nor the Regulations mandate that work must be done for the purpose of meeting these Essential Requirements. But both require that, in particular circumstances, where work is being done, the outcome must satisfy the Essential Requirements.
• The Directives divide the trans-European rail system into "subsystems", each of which has to comply with the essential requirements as specified for that particular sub-system;
• Common characteristics of subsystems (and their interfaces) for which the essential requirements must be met are set out in detail in Technical Specifications for Interoperability (TSIs). Compliance with the TSIs is mandatory, and where the TSIs specifically mandate European standards, compliance with those standards also becomes mandatory;
• In cases where, for example, a TSI has yet to be published, where there are open points in a published TSI, or where a derogation has been made, then a national technical rule may be applied instead of a TSI to give effect to the essential requirements, so long as it has first been notified to the Commission and to other Member States;
• There is scope for the Member State to derogate from compliance with the TSIs, or parts of them, under certain circumstances;
• The TSIs also define "interoperability constituents" relating to each subsystem. The interoperability constituents are identifiable parts or groups of parts which must meet the essential requirements when placed on the market for use within the trans-European rail network;

Details of how constituents can meet the essential requirements in practice are described in European standards or in the latest draft version where no European standard is in force.

Common checking and authorisation process

For subsystems, the checking and authorisation processes can be summarised as follows:

• From the outset of a new project, the body commissioning the works - known as the Contracting Entity - must decide whether the project being undertaken is prospectively subject to assessment and authorisation requirements as construction of a new part of the trans-European rail system or as major works constituting upgrade or renewal;
• Where new construction is concerned, authorisation will be needed to bring the completed works into service;
• In the case of upgrade or renewal the Contracting Entity must apply to the Competent Authority (DfT for GB, IGC for Channel Tunnel and DRDNI in Northern Ireland) for a decision as to whether authorisation is necessary;
• Where authorisation is necessary, the Contracting Entity must engage a Notified Body (NoBo) to assess whether the subsystems involved comply with the relevant TSIs
• The engaged NoBo will verify satisfaction of the essential requirements by assessing the subsystem's conformance with the TSIs and the relevant national technical rules relating to the project work. The NoBo also verifies the interfaces (i.e. compatibility) with the rest of the system into which it is to be integrated. The NoBo issues a certificate of conformity and prepares a technical file;
• The Contracting Entity can then draw up a verification declaration declaring compliance with the essential requirements and citing the NoBo's assessment as a demonstration of this;
• The Contracting Entity seeks authorisation to place the subsystem into service by forwarding the verification declaration, certificate of conformity and the complete technical file to the appropriate Safety Authority;
• The Safety Authority determines whether or not to give authorisation for the subsystem concerned to be placed in service.

Subsequent use of the authorised subsystem requires continuing conformity with the essential requirements. The Regulations require the operators of authorised subsystems to ensure that the subsystems continue to conform to the TSIs and notified national technical rules that the scheme was assessed against, and the contracting entity to maintain the technical file.

Interoperability and safety

The Interoperability Regulations, alongside ROGS, establish a seamless and complementary framework for the delivery of interoperability standards and railway safety. In very simple terms:

• Interoperability is concerned with concept, design, build, and authorisation to place a new, renewed, or upgraded asset into service;
• ROGS is concerned with the ongoing safe operation of that asset.

Interoperability does not deliver a higher level of safety than ROGS.

The purpose of the Regulations is to ensure that new build, or major work on existing assets, contributes to an increase in the overall interoperability of the European network, and brings with it the benefits of economies of scale.

Interoperability and key safety characteristics of design and build are delivered standardising the interfaces between subsystems to deliver compatibility. The approval process moves from being one which tests every interface to one which verifies that standards - which are already known to achieve a safe interface - have been met. As standardisation progresses, so the barriers to cross-acceptance and the through-running of trains are lowered.