In the German railway sector, the fourth railway package was implemented in 2020. The railway infrastructure company (RIC) DB Netz AG is now obliged to carry out, for pending ETCS/GSM-R projects, the trackside approval process (TA process) with the European Union Agency for Railways (EUAR). In the national legislation, the German Railway Commissioning Approval Regulation (EIGV) requires the TA process to be completed as a binding prerequisite for the commissioning approval of the control-command and signalling (CCS) subsystem. SIGNON is supporting the RIC, DB Netz AG, with the TA process. The focus is on fulfilling the specialist requirements of the functions list and issues log (F+I). For this, the EUAR is calling for reliable solutions to be demonstrated for the respective project, depending on the relevant ERTMS functions. This involves demonstrating transparent references to regulations, performance specifications, designs, custom solutions etc. for the CCS subsystem. The F+I list is the core part of the TA process with the EUAR and is decisive for successful completion. SIGNON is in direct contact with DB Netz AG, participates in project alignments and provides expertise for the follow-up questions from EUAR that arise.