However, during the late 2010s, the ETCS programme reportedly ran into issues with the retrofitting of existing rolling stock to use the new signalling system; the IC3 fleet of long distance diesel multiple units proved to be a particular source of problems, thus the end date of the rollout was postponed considerably. Freight operators were also reportedly unable to upgrade some of their locomotives to be ETCS compatible yet. These difficulties were in part compounded by the sweeping scale of the programme; no other nation had attempted such a conversion before and was regarded as one of the largest resignalling schemes in the world. During August 2022, it was announced that work to replace legacy signalling with ETCS on the Holstebro - Herning and Vejle - Skanderborg lines in Jutland had been completed; it was anticipated that the ETCS rollout would continue through to 2030. Advantages of the new signalling included better train punctuality, more stable operation, and more detailed traffic information.
