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​​​​​​​​​​​​​​​​​​​​​​​​​​​The European Rail Traffi​c Management System (ERTMS) External link comprises of the European Train Control System (ETCS), the Global System for Mobile communications – Railway (GSM-R), Traffic Management Systems (TMS) and operating rules.  Technical specifications for ETCS and GSM-R are published in the Control Command and Signalling (CCS) Technical Specification for Interoperability (TSI) cab-signalling system that incorporates automatic train protection.  GSM-R provides voice communication for train drivers and signallers and provides data communication for ETCS. ERTMS and GSM-R rules are published in the OPE TSI.

In May 2001 a national programme was created for the application of the European Rail Traffic Management System (ERTMS) in Great Britain.  This programme has been included and updated in cross industry work to form part of the national operation strategy, led by Network Rail.  This programme is cross-industry and is currently led by Network Rail; RSSB is a partner in this programme.  RSSB provides operations, engineering, human factors and safety risk expertise for the application of ERTMS in Great Britain.  This application is in accordance with the specifications published by the European Railway Agency and is supported by complementary national requirements, standards and operational rules.

The deployment of ERTMS features heavily in the Industry Strategic Business plan for the period 2014-2019 (Control Period 5) and beyond and ERTMS is an enabler for the RSSB Innovation programme External link.  RSSB is working with other industry partners to help achieve the application of ERTMS on the mainline railway infrastructure and trains that operate on it. 

The first application of ERTMS in service in Great Britain is the Cambrian Line in Wales, operating from just outside Shrewsbury to Aberystwyth and Pwllheli. Through engagement in the national programme, RSSB has supported this application by developing standards, operational rules (including the Rule Book) and other documentation, such as user procedures.  The Rule Book and other materials published by RSSB are available electronically through the Railway ​Group Standards​ section of this site.

For further information on RSSB's involvement please email: or phone: +44 (0)20 3142 5400.

Further information is also available from ERTMS Online External link.

ERTMS documentation

In addition to the material published in the Standards catalogue, RSSB has published other documents and undertaken research on ERTMS.  The outputs of ERTMS-related research projects are available on SPARK External link.

Rule Book amendments

Following the full commissioning of the Cambrian Line in March 2011, amendments to the Rule Book modules have been published in the Network Rail Western Route ERTMS Periodic Operating Notice (PON) supplement. For the benefit of those not in receipt of this document, here is the source document produced by RSSB for the rule amendments published in the PON.

ERTMS National Values – Overview

ERTMS provides a number of system variables called ERTMS National Values that can be varied to fit specific safety and operational performance objectives. These ERTMS National Values cover many aspects of ERTMS operation, including, for example, the maximum speeds permitted under different modes of operation. These values are typically defined during the design phase of the application and are configured through the software application of the system. A country may adopt different sets of national values to suit particular safety or operational requirements on different routes, but cannot adopt different national values over the same route.

ERTMS National Values - D_NVROLL

D_NVROLL specifies the distance to be used in roll away protection, reverse movement protection and standstill supervision before onboard ERTMS equipment demands a brake application.

D_NVROLL is a trackside parameter which is used to configure the behaviour of the onboard. It is uploaded to the train when the train transitions into a new area, or at startup.  Prior to this the train retains its previous set of national values.  A default value for D_NVROLL is defined, but this is only used if no other value has ever been uploaded.

The ERTMS National Values – D_NVROLL document has been produced by RSSB on behalf the National Operation Strategy to define one of the nationally defined values (D_NVROLL).

ERTMS Business Requirements

In April 2012 the ERTMS Strategy Group endorsed the publication of the ERTMS Business Requirements.  The business requirements were developed to satisfy five needs, to:

  • Provide a means to contribute towards the delivery of the rail industry strategy as set out in the Rail Technical Strategy and controlled by Technical Strategy Leadership Group.
  • Provide direction to the ERTMS Programme Control Board, particularly in respect of the National Generic ERTMS Principles.
  • Provide guidance to the National ERTMS Programme and delivery projects in their deployment of ERTMS.
  • Contribute to the development of a high-technology railway.
  • Contribute to the development of a competent, appropriately skilled workforce.

The National ERTMS business requirements document is available here.

ETCS requirements suite

The cross-industry ERTMS Programme, now part of Digital Railway, has worked collaboratively to produce a set of requirements to support the national procurement on ETCS.

The following documents were authorised for publication on the 31st March 2017.

  1. ETCS – Baseline 3 - System Requirements Specification, NEPT/ERTMS/REQ/0005, Issue 4.0
  2. ETCS – Baseline 3 – GB Trackside Subsystem Requirements Specification, NEPT/ERTMS/REQ/0006, Issue 2.0
  3. ETCS – Baseline 3 – GB Onboard Retrofit Subsystem Requirements Specification, NEPT/ERTMS/REQ/0007, Issue 3.0
  4. ETCS – Baseline 3 – GB Onboard New Trains Subsystem Requirements Specification, NEPT/ERTMS/REQ/0038, Issue 2.0
  5. ETCS – Baseline 3 – GB Telecoms Subsystem Requirements Specification, NEPT/ERTMS/REQ/0008, Issue 3.0
  6. ETCS – Baseline 3 – GB Operational Subsystem Requirements Specification, NEPT/ERTMS/REQ/0009, Issue 2.0

Please be aware that this issue enables Digital Railway to place all the requirements under full configuration management control, but it is not the final step as there are several update events identified e.g. incorporating ATO and Level 3 input. These update events will also give opportunities for including the necessary changes arising from further development and closure of the identified open points.

All the specifications have been written to comply with the ERA specifications for ERTMS Baseline 3 and each requirement includes rationale and guidance where appropriate.

Note: ETCS Onboard System – Baseline 3 – National Onboard Subsystem Requirements Specification NEPT/ERTMS/REQ/0007 Issue 2.0 (which was previously published on this web page) has been superseded by the specifications listed in items 3 and 4 above.

These specifications are managed by Digital Railway; it is made available here on behalf of Digital Railway. As experience is gained with the application of the requirements in the specification, it is expected that relevant requirements will be incorporated into standards listed in the catalogue of Railway Group Standards at some time, yet to be determined.

If you would like to discuss any of these specifications, or have identified any errors or potential improvements, then please e-mail:

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