From 1 January 2021, the Railways (Interoperability) Regulations 2011 (as amended), requires the Secretary of State to publish a list of all national technical rules (NTRs) that apply in the UK.  NTRs are contained in Railway Group Standards (RGSs).  The RGSs in the list replaces those that were previously notified national technical rules (NNTRs) prior to the ending of the transition period on 31 December 2020.  Technical Specifications for Interoperability (TSIs) were replaced by NTSNs on 1 January 2021.  For more information on NTSNs refer to National Technical Specification Notices (

NTRs can be provided in situations such as:

  • To fill identified 'open points' in NTSNs. Open points are identified in an annex to an NTSN if certain technical aspects corresponding to the essential requirements cannot be explicitly covered in the NTSN.
  • To support ‘UK specific cases’ in NTSNs. A UK specific case is a special provision relating to the technical specifications for a subsystem or an interoperability constituent to allow for its compatibility with the rail system, which is set out in an NTSN or an NTR.
  • To set out requirements to maintain technical compatibility between existing assets (or processes) that do not conform to the requirements of NTSNs and new, upgraded or renewed assets that do conform to NTSNs.

NTRs are not permitted to supplement the NTSNs on performance related issues or repeat requirements mandated by the NTSNs.

NTRs are intended for use by project entities on the GB mainline railway, as defined in the Railways (Interoperability) Regulations 2011 (as amended).

The industry process to be used for identifying and managing NTRs for the GB mainline railway is set out in the Railway Standards Code

Publication of NTRs

On behalf of the industry, RSSB proposes a list of NTRs (standards) to the Department for Transport (DfT) that the Secretary of State considers for publication. The Secretary of State may publish additional requirements to ensure that all essential requirements are addressed by the NTRs.

NTRs are subject to periodic review as the status of the NTSNs changes and GB RGSs are developed or withdrawn. Current NTRs are published on the DfT’s website