Division 4.2.1 Control-Command safety characteristics relevant to interoperability

This Basic Parameter describes the safety requirements for ERTMS/ETCS on On-board assemblies and the safety requirements on Track-side assemblies.

With reference to the Essential Requirement ‘safety’ (see section 3.2.1, Safety), this Basic Parameter establishes the mandatory requirements for interoperability:

• To ensure that the solutions to achieve safety do not jeopardise interoperability the requirements of Annex A, Index 47 shall be respected.

• For the safety related part of one On board Assembly as well as for one Track-side Assembly, the safety requirement for ETCS level 1 or level 2^f1 is: tolerable hazard rate (THR) of 10^-9/hour (for random failures) corresponding to Safety Integrity Level 4. The detailed requirements for Class A equipment are specified in Annex A, Index 27. Less restrictive safety requirements on THR values for Track-side equipment may be adopted, provided that the safety objective for the service is met.

• The reliability and availability requirements of Annex A, index 28 shall be respected.