# Commission Decision of 7 November 2006 concerning a technical specification for interoperability relating to the control-command and signalling subsystem of the trans-European high speed rail system and modifying Annex A to Decision 2006/679/EC concerning the technical specification for interoperability relating to the control-command and signalling subsystem of the trans-European conventional rail system (notified under document number C(2006) 5211) (Text with EEA relevance) (2006/860/EC), Division: On-board installations:

Extent: E+W+S+N.I.

It is mandatory to fit a GSM-R onboard assembly when:
any new radio part of a CCS onboard assembly is installed (with or without a Class B system), or;
any existing radio part of a CCS onboard assembly is upgraded, where this would change the functions, performance and/or interfaces of the existing legacy system (as referred to in annex B of this TSI). This excludes those modifications that might be deemed necessary to mitigate safety-related defects in the legacy system.
After an upgrade of the radio part of an onboard assembly, the pre-existing Class B equipment may remain in use simultaneously with the Class A radio equipment.

---
Source: https://www.legislation.gov.uk/eudn/2006/860/annex/division/7/division/7.2/division/7.2.1/division/2 (the official version)
Page: https://openlegislation.uk/eu-decision-2006-860/annex/division-7/division-7.2/division-7.2.1/division-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.