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Project number: 2024-STN-102

General guidance for National Technical Specification Notices (NTSNs)

A new Guidance Note (GEGN8601 issue 1) with topics for multiple NTSNs
'GEGN8601 is a much-needed, helpful, and valuable resource for strengthening industry-wide understanding of NTSNs.'
Brian Tomlinson
Chief Systems Engineer, Network Rail
The challenge

NTSNs were published by the Department for Transport in January 2021 and May 2025.

NTSNs do not contain guidance. NTSN-specific Guidance Notes published by RSSB focus on specific technical requirements in NTSNs, rather than general aspects.

Issues addressed by this work are:

  1. Filling gaps in guidance, partly due to EU-Exit.
  2. Addressing industry queries that are regularly raised.
  3. Avoiding duplication in all of RSSB’s NTSN-specific Guidance Notes.
  4. Bringing together various pieces of existing information, including from DfT, ORR, and RSSB webpages and documents, into a single source.

Therefore, objectives for this work were to:

  1. Provide guidance for industry on the general application of NTSNs
  2. Establish a clear and consistent structure for general NTSN guidance.
What we did

RSSB developed a new Guidance Note, GEGN8601 issue 1, to cover topics relevant to multiple NTSNs. It includes the regulatory context for NTSNs, roles and responsibilities, links between NTSNs and other standards or documents, implementation, and conformity assessment.

The guidance combines, updates and fills gaps in existing guidance, to put relevant industry-agreed information in a single place.

The focus of the guidance is on implementation, including transition regimes between different NTSNs and conformity assessment.

As well as enhancing existing NTSN guidance, the work included analysis and incorporation of relevant EU guidance for Technical Specifications for Interoperability, including guidance produced by the European Union Agency for Railways and NB-Rail.

Benefits delivered

The benefits include:

  • Clearer understanding for projects, supporting more efficient delivery through reduced volume of discussions and questions.
  • Potential cost savings for projects through correct application, rather than misinterpretation that can result in requiring rework.
  • Promotion of consistent application and helping to deliver on the requirements set out in the NTSNs.
  • Reduced risk of disagreement in applying NTSNs within projects, with conformity assessors, with the ORR, and with the DfT.

It will provide the industry with benefits ranging from £80k to £200k over the next five years.