In an updated special report, the European Court of Auditors (ECA) states that the core network of the trans-European transport network TEN-T will not be completed by 2030. Eight mega-projects examined have seen massive cost increases and delays. In real terms, project costs have increased by an average of 82% since the original estimates. The high-speed rail (HSR) lines Rail Baltica and Lyon – Turin are particularly affected. EU co-financing for the eight mega-projects has increased by EUR 7.9 billion since 2020 to a total of EUR 15.3 billion. In terms of time, the five projects with reliable data are on average 17 years behind schedule. For example, the start of operation of the Basque Y HSR line, Lyon – Turin and Brenner Base Tunnel has been postponed to the 2030s. The auditors criticise the European Commission (EC) for making little use of its central instrument of intervention under the TEN-T Regulation to date, but expect the recently revised TEN-T Regulation to give the EC a stronger role in supervising future projects, provided that Member States implement the rules consistently.