Guidance

Railway interoperability glossary

Published 19 January 2022

Applies to England, Scotland and Wales

Approved body (AB)

Approved bodies are independent third parties appointed by the Secretary of State and which meet the criteria of competence, integrity and independence as set out in Schedule 8 of RIR 2011.

Approved bodies assess and verify conformity of project subsystems to national technical specification notices (NTSNs). They operate in tandem with designated bodies who assess and verify conformity with national technical rules (NTRs).

Since the UK has withdrawn from the EU, notified bodies that were previously notified and appointed by the Secretary of State for Transport have become approved bodies.

Authorisation (APIS or APS)

An authorisation to place in service is a document issued by the safety authority in accordance with Regulation 7(1) of RIR 2011.

Note: place in service is defined as all the operations by which a subsystem is put into its design operating state. The authorisation is required when the subsystem is put into use (first used after being constructed, upgraded or renewed on or as a part of the UK rail system).

Note: this is not the safety authorisation issued to infrastructure managers under the Railways and Other Guided Transport Systems (Safety) Regulations 2006.

Common Safety Methods (CSMs)

Common Safety Methods are an approach to describe how safety levels, achievement of safety targets and compliance with other safety requirements are assessed. They apply whenever a change of the operating conditions or new material imposes new risks on infrastructure or operations.

Competent authority (CA)

A competent authority (CA) is the body responsible for securing the effective implementation of interoperability in the UK. This includes, for example, amending the interoperability framework, setting technical standards by publishing the NTSNs (regulation 3B of RIR 2011), taking decisions as to whether an authorisation is required for upgrades or renewals (regulation 13) and determining exemptions from all, or part, of an NTSN (regulation 14).

The United Kingdom has 2 CAs, which are for:

• England, Wales, Scotland and the UK half of the Channel Tunnel, the Secretary of State for Transport
• Northern Ireland, the Department for Infrastructure (DFI)

Contracting Entity (CE)

The definition used in RIR 2011 is: ‘the person who contracts or intends to contract with another person for that other person to design, construct, renew or upgrade a subsystem’ (see Project entity).

Department for Infrastructure (DFI)

The Department for Infrastructure is responsible for:

• strategic planning
• transportation strategy
• ports and public transport
• roads and water policy
• providing and maintaining roads in Northern Ireland

DFI is the safety authority and the competent authority for Northern Ireland.

Department for Transport (DfT)

The Department for Transport is the central government body that provides leadership across the transport sector. It is responsible for the development and implementation of the legislative framework under which interoperability operates in the UK.

DfT, in the person of the Secretary of State for Transport, is also the competent authority for Great Britain.

Designated body (DeBo)

Designated bodies (DeBos) are independent third parties appointed by the Secretary of State for Transport to assess and verify conformity of projects with NTRs in the UK.

They operate in tandem with approved bodies which assess and verify conformity with NTSNs.

Regulation 31 of RIR 2011 provides for the appointment of approved bodies and designated bodies.

Directive

A Directive is a legislative act of the European Union that requires member states to achieve a particular result within a set timetable usually without dictating the means of how this should be achieved.

EU Directives no longer apply in Great Britain (GB). However, there may be some circumstances where there will be references to an EU Directive under the UK regime, such as technical files that contain documentation issued before the UK left the EU.

EC certificate of verification

An EC certificate of verification is a document drawn up by a notified body (NoBo) in relation to a structural subsystem as part of the EC verification assessment procedure.

Enforcing authority

An enforcing authority is a body required to make adequate arrangements for the enforcement of RIR 2011. Regulations 39 and 40 of RIR 2011 prescribe offences and penalties for breaches. The enforcing authority in Great Britain (including the UK half of the Channel Tunnel) is the Office of Rail and Road. For Northern Ireland, it is the Health & Safety Executive for Northern Ireland.

Entity in charge of maintenance (ECM)

An entity in charge of maintenance is a body that ensures rail vehicles for which it has responsibility are kept in a safe state of running by means of a system of maintenance.

The Railways and Other Guided Transport Systems (Safety) Regulations 2006 (ROGS) requires each vehicle, before it is placed in service or used on the network, to have an ECM assigned to it and registered in the National Vehicle Register (NVR).

An ECM is anyone responsible for the safe maintenance of a vehicle and registered as the ECM in the national vehicle register.

Essential requirements

The essential requirements are the 6 conditions (safety, reliability and availability, health, environmental protection, technical compatibility and accessibility) that must be met by the rail system, subsystems and interoperability constituents, including interfaces.

Further information on the requirements is contained in Schedule 2 of RIR 2011. These are deemed to be met by complying with NTSNs and NTRs.

EU interoperability directives

The 4 previous interoperability directives, that applied to EU member states, were revoked and replaced by a single, recast, Directive (2008/57/EC) in 2008.

The previous interoperability directives were:

• Directive 96/48/EC on the interoperability of the trans-European high-speed rail system
• Directive 2001/16/EC on the interoperability of the conventional rail system
• Directive 2004/50/EC which amended the first two rail Interoperability Directives
• Directive 2007/32/EC which introduced Intermediate Statements of Verification (‘ISVs’)

Directive 2008/57/EC has subsequently been amended 5 times by directives 2009/131/EC, 2011/18/EU, 2013/9/EU, 2014/38/EU and 2014/106/EU.

Directive 2016/797/EU has revoked and replaced Directive 2008/57/EC, but this latest Directive has not been implemented in GB.

Euro Norm (EN)

A Euro Norm is a standard issued by the European Committee for Standardisation (CEN) or the European Committee for Electrotechnical Standardisation (CENELEC).

The British Standards Institution is the national issuing body for Great Britain where EN standards have the prefix ‘BS EN’.

European Railway Traffic Management System (ERTMS)

The European Railway Traffic Management System (ERTMS) is an in-cab signalling system for trains. The aim is to eventually replace the different train control and command systems currently in use across the UK.

A plan for the implementation of ERTMS in the United Kingdom is available.

European vehicle number (EVN)

A European vehicle number is a unique, 12-digit numeric identification code issued to all rail vehicles in accordance with Annex H of the NTSN for traffic operation and management (ODT, 252KB).

Exemption

Project entities can apply to the competent authority (DfT) for an exemption (formerly known as a derogation) from the requirement to comply with all, or part, of an NTSN. Exemptions may be permitted in relation to a specific project in the circumstances provided for by regulation 14 of RIR 2011.

Project entities should seek early engagement with the relevant competent authority to discuss any proposed exemption requests.

Functional subsystem

Functional subsystems are those which deal with traffic operation and management, maintenance or telematics applications for passenger and freight services. These subsystems are critical to railway operation but do not require authorisation as part of the design and build.

A list and description of the different subsystem types can be found in Schedule 3 of RIR 2011.

Great Britain (GB)

Great Britain comprises England, Scotland and Wales. This includes certain outlying islands including the Isle of Wight, Anglesey, the Scilly Isles, the Hebrides, Orkney and Shetland.

It does not include the Isle of Man or the Channel Islands.

Implementation plans (IPs)

An implementation plan is a document that sets out how the UK will implement NTSNs. Chapter 7 of each NTSN contains a strategy for how it should be implemented and includes, for example, its application to new and existing subsystems and any specific cases that may be applicable.

IPs are published on GOV.UK.

Infrastructure

Infrastructure subsystems include, for example, track, points, engineering structures (bridges, tunnels), associated station infrastructure (platforms, zones of access, including the needs of persons with reduced mobility), safety and protective equipment. However, power supply and signalling are also often included.

Infrastructure owner

An infrastructure owner is any person who has an estate or interest in, or right over the infrastructure and whose agreement is needed before another may use it. Regulation 35 of RIR 2011 requires an owner of infrastructure to keep a register of infrastructure, or procure that one is kept, in accordance with Decision 2014/880/EU on the common specifications of the register of railway infrastructure.

Interface

Method, or equipment, for interconnecting subsystems that may not otherwise be directly compatible. The UK approved body has a role in assessing the interface between the project subsystem and the rail system under regulation 17 of RIR 2011.

Intergovernmental Commission (IGC)

The Intergovernmental Commission was established by the Treaty of Canterbury in 1986. Its roles include being the safety authority for the Channel Tunnel.

Intermediate Statement of Verification (ISV)

Intermediate Statements of Verification (ISV) enable checks to be carried out in stages – see Schedule 4 of RIR 2011.

ISVs can be issued by:

• an approved body in relation to the design stage or the production stage of a subsystem in accordance with section 2 of Schedule 4
• an EU notified body in relation to the design stage or the production stage of a subsystem in accordance with section 2 of Annex VI to the Directive
• a designated body at an intermediate stage of the verification assessment procedure referred to in section 3 of Schedule 4
• a designated body at an intermediate stage of the verification assessment procedure referred to in section 3 of Annex VI to the Directive

Interoperability

At its most basic level, interoperability is the ability of a system or a product to work with other systems or products without special effort on the part of the customer.

For example, all domestic electrical products on sale in the United Kingdom, such as hairdryers and drills, have the same plug. Interoperability is made possible by the implementation of standards.

In the rail industry, interoperability is defined as ‘the ability of a rail system to allow the safe and uninterrupted movement of trains which accomplish the required levels of performance for these lines. This ability depends on all the regulatory, technical and operational conditions which must be met to satisfy the essential requirements.’

The purpose of the rail interoperability regime is therefore to promote compatibility in the rail sector by providing for harmonious technical standards and a common assessment and authorisation process for bringing into operation new rail developments, upgrades or renewals of existing subsystems.

Interoperability constituent (IC)

An interoperability constituent (IC) means any elementary component, group of components, sub-assembly or complete assembly of equipment that is incorporated or intended to be incorporated into a subsystem upon which the interoperability of the rail system depends directly or indirectly and includes both tangible objects and intangible ones such as software.

Member state (MS)

A country that is a member of the European Union.

National technical rules (NTRs)

National technical rules are the standards, technical specifications and technical rules that are applicable in the UK. Compliance with NTRs must be verified by a designated body.

NTRs are used for the following purposes:

• to cover the parts of the rail system out of scope of NTSNs
• to address open points or specific cases in NTSNs
• to ensure technical compatibility between vehicles and the rail system
• to provide alternative provisions that will be applied if an exemption against an NTSN has been granted by the competent authority for a project.

The list of NTRs may be varied from time to time by the Secretary of State for Transport and any variation to the list will be published by the Secretary of State on the DfT website.

National technical specification notice (NTSN)

A national technical specification notice outlines the specification to be met by a subsystem, or part subsystem, for it to meet the essential requirements and achieve interoperability of the rail system in GB. NTSNs apply to the GB rail system, with certain exclusions provided for in regulation 3 of RIR 2011.

NTSNs have replaced TSIs as the applicable standards in GB (but TSIs continue to apply in NI). NTSNs substantially reproduce the TSIs but where divergence occurs, it is included in NTSNs as UK specific cases.

National Vehicle Register (NVR)

The National Vehicle Register is a database of the unique numbers and other critical management and safety data about all rail vehicles operated in the UK. The format and data which must be recorded are set out in Decision 2007/756/EC as amended by Decision 2011/107/EU.

The UK has designated registration entities that are responsible for keeping and updating its NVR. These are for:

• Great Britain, Network Rail Infrastructure Limited
• Northern Ireland, the Department for Infrastructure (DFI)

Regulation 36 of RIR 2011 contains provisions relating to the NVR.

Notified body (NoBo)

Notified bodies (NoBos) are independent third parties appointed by European Union member states that meet the criteria of competence, integrity and independence set out in Directive 2016/797.

NoBos assess and verify conformity of project subsystems to the TSIs. They operate in tandem with EU designated bodies (DeBos) that assess and verify conformity with EU member states’ NNTRs.

Since the UK has withdrawn from the EU, NoBos that were previously appointed by the Secretary of State for Transport have become approved bodies.

Office of Rail and Road (ORR)

The Office of Rail and Road is the independent safety and economic regulator for the majority of the rail industry in GB. It is responsible for the enforcement of RIR 2011 in GB.

Open point

An open point occurs if, during the development of an NTSN, the Secretary of State for Transport considers that an appropriate specification cannot be agreed for a particular aspect of any essential requirement.

If present, open points are clearly identified in an annex to a published NTSN. Once in force, NTRs will be published that apply to projects to fill any open points.

Project entity

RIR 2011 defines a project entity as a shorthand term to cover a contracting entity or manufacturer or the authorised representative of a contracting entity or manufacturer.

Rail system

The rail system is the railway structure composed of lines, fixed installations and vehicles. The scope of the regulations is the parts of the rail system located in the UK. There are a number of categories excluded from scope under regulation 3 (such as metros, trams and other light rail systems).

Railways (Interoperability) Regulations 2011 (RIR 2011)

The Railways (Interoperability) Regulations 2011 concerns a set of common rail technical standards and approval processes.

It provides for a common system of technical standards and authorisation to help remove barriers to approvals.

These standards apply to the authorisation by the safety authority of new rolling stock and infrastructure to be placed into service.

RIR 2011 has been amended by SI 2013/3023, SI 2014/3217, SI 2015/2022 and SI 2019/345, SI 2019/1310, SI 2020/318 and SI 2020/786.

RIR 2011 has been amended to ensure that the UK’s interoperability regime continues to function effectively now that the UK is no longer a member of the EU.

Railways and Other Guided Transport Systems (Safety) Regulations 2006 (ROGS)

The Railways and other Guided Transport Systems (Safety) Regulations 2006 concern the mechanisms for placing subsystems into service and ongoing operational safety requirements.

ROGS is amended by SI 2006/1057, SI 2007/3531, SI 2010/439, SI 2011/1860, SI 2013/950 and SI 2015/1917.

Registration entity

The entity responsible for the keeping and updating the NVR. For Great Britain, the Secretary of State for Transport has designated Network Rail Infrastructure Limited to perform this function.

DFI is the registration entity for Northern Ireland.

Renewal

Renewal is any major substitution work on a subsystem or part subsystem that does not change the overall performance of the subsystem.

Renewal triggers the need for compliance with RIR 2011.

Under regulation 12 of RIR 2011, the competent authority may publish lists of projects (by name or description) that are deemed to be upgrade and renewal and require authorisation (unless a decision is given by the competent authority that authorisation is not required).

Safety authority (SA)

A safety authority (SA) is the body entrusted with tasks regarding railway safety. There are 3 SAs in the UK for:

• Great Britain, the Office of Rail and Road (ORR)
• Northern Ireland, the Department for Infrastructure (DFI)
• the Channel Tunnel, the Intergovernmental Commission (IGC). (Subject to future change.)

Note: Under RIR 2011 the safety authorities are responsible for issuing authorisations to place into service.

Structural subsystem

Structural subsystems are those which deal with rolling stock, infrastructure, energy or control and command and signalling.

A list and description of the different subsystem types can be found in Schedule 3 of RIR 2011.

Subsystem

A categorisation of the rail system into separate elements for convenience in the context of interoperability. The term is used to refer to the whole, or any part of ‘structural’ or ‘functional’ subsystems.

A list and description of the different subsystem types can be found in sections 1(a) and 1(b) of Schedule 3 of RIR 2011.

Technical specification for interoperability (TSI)

A technical specification for interoperability is the EU specification to be met by a subsystem, or part of a subsystem, to meet the essential requirements and achieve interoperability of the rail systems fo EU member states.

Since the UK is no longer a member of the EU, TSIs do not apply to the GB rail system. These have been replaced by NTSNs. There are, however, instances where conformity assessment against TSIs will be recognised for authorisation to place into service in the UK, such as when TSIs and NTSNs remain aligned.

Trans-European rail system (TEN)

The trans-European rail system or network means the trans-European conventional and high-speed rail systems as set out in sections 1 and 2 of Annex I of Directive 2008/57/EC on Exit Day.

UK certificate of verification

A UK certificate of verification is a document drawn up by an approved body or a designated body (DeBo) in relation to a structural subsystem as part of the UK verification assessment procedure.

UK declaration of conformity or suitability for use

The UK declaration of conformity or suitability for use applies to the interoperability constituents involved in the interoperability of the rail system.

A UK declaration of conformity or suitability for use is required to be drawn up before an interoperability constituent is placed on the market with the intention of it being used on the rail system.

An EC declaration of conformity or suitability for use is acceptable only in certain circumstances (see regulation 23 of RIR 2011 for further information).

UK specific case

UK specific cases are special provisions in relation to the technical specifications for a subsystem or an interoperability constituent to allow for its compatibility with the rail system. These are set out in NTSNs and may refer to an NTR.

Divergence from EU TSIs will be included as UK specific cases in NTSNs, to provide clarity about how standards within a NTSN could diverge from the standards contained in the TSI.

UK specific rules

UK specific rules are all UK specific cases and NTRs, including any dispensation granted against NTRs.

UK verification assessment procedure

The process of assessment by an approved body or designated body that a project conforms respectively with NTSNs or NTRs in accordance with regulation 17 and Schedule 4 of the RIR 2011.

United Kingdom (UK)

The United Kingdom means Great Britain (England, Scotland and Wales) and Northern Ireland.

United Kingdom Accreditation Service (UKAS)

The United Kingdom Accreditation Service is the national accreditation body recognised by the government to assess against agreed standards, organisations that provide certification, testing, inspection and calibration services.

UKAS assesses prospective approved bodies and designated bodies against the criteria in Schedule 8 of RIR 2011, setting out the minimum criteria which must be taken into account by the Secretary of State for Transport when approving bodies.

It also monitors the performance of appointed UK approved bodies. A similar process of UKAS recommendation of appointment and monitoring will also apply to designated bodies.

Upgrading

Upgrading means any major modification work on a structural subsystem or part of a structural subsystem that improves overall performance.

Upgrading triggers the need for compliance with RIR 2011.

Under regulation 12 of RIR 2011, the competent authority may publish lists of projects (by name or description) that are deemed to be upgrade and renewal and require authorisation (unless a decision is given by the competent authority that authorisation is not required). However, such a list has not been published to date.