Rail interoperability: National Technical Specification Notices (NTSNs)
UK railway technical standards, known as NTSNs, have replaced EU technical specifications for interoperability (TSIs).
National Technical Specification Notices (NTSNs) have been published by the Secretary of State for Transport pursuant to regulation 3B of the Railways Interoperability Regulations 2011.
The first editions of the 11 NTSNs for Great Britain (GB) were published on 1 January 2021.
Following a substantial NTSN revision exercise, which was informed by an industry consultation, we published updated editions of 7 NTSNs on 2 May 2025. They apply in GB only.
The EU Technical Specifications for Interoperability (TSIs) continue to have direct effect in Northern Ireland.
These NTSNs set standards to be complied with in relation to the design, construction, placing in service, upgrading, renewal, operation and maintenance of the parts of the rail system, as well as the professional qualifications and health and safety conditions of the staff who contribute to its operation and maintenance.
The 11 NTSNs replace the TSIs for GB. They are:
- Safety in Railway Tunnels (SRT)
- Control Command and Signalling (CCS)
- Operation and Traffic Management (OPE)
- Infrastructure (INF)
- Energy (ENE)
- Rolling Stock – Locomotive and Passenger (LOC and PAS)
- Rolling Stock – Noise (NOI)
- Rolling Stock – Freight Wagons (WAG)
- Accessibility (ACC) (formerly called Persons with Reduced Mobility (PRM))
- Telematics Applications for Passenger Services (TAP)
- Telematics Applications for Freight (TAF)
The Modules NTSN replaces and substantially reproduces requirements within Commission Decision 2010/713/EU of 9 November 2010 on modules for the procedures for assessment of conformity, suitability for use and EC verification to be used in the technical specifications for interoperability.
The NTSN concerning the assessment of interoperability constituents against UK-specific cases, including the further assessment of interoperability constituents which hold an EC declaration of conformity or suitability for use, sets out the procedure that must be followed in accordance with regulation 24(1) and (2) of the Railways (Interoperability) Regulations 2011.
The Department for Transport (DfT) worked with RSSB to create the NTSNs.