ERTMS/ETCS is now a credible system and available for implementation. It is especially suitable for new lines. ERTMS/ETCS includes the GSM-R radio system as the essential transmission path between track and train. ERTMS/ETCS is available in both Level 1 and Level 2 variants, with Level 3 still to be developed. ERTMS/ETCS has been in commercial operation in various countries since 2005/2006 (Germany, Italy, Luxembourg, the Netherlands, Spain, Switzerland) and will be implemented in other countries soon, including Austria, Belgium and Hungary. Over 600 vehicles in more than 20 differing types of rolling stock are running each day (Levels 1 and 2) and much experience has been gained to enable the production of the latest technical baseline (known as version 2.3.0), which is expected to provide interoperability. With this important deployment step, ETCS will be confirmed as the future Automatic Train Control system for all principal lines in most European countries and elsewhere in the world. Once in service, the performance of ERTMS/ETCS (in terms of reducing train delay minutes) already seems to be even better than the railways’ initial predictions and targets, e.g. as seen in Switzerland. The present article includes information about some of the “Lessons Learnt” from these first projects, points that the other railways should consider closely when introducing ERTMS/ETCS. Of course, and this is normal for any new system, there are still areas that need refinement, both with operational aspects and in the manufacture of the products, both of which are being addressed by the railways and the supply industry (UNIFE/UNISIG).