The reform of railway regulation is a complex field and many details are of utmost importance both for the understanding of the functioning of the models and for the success of their implementation. Pure models do not exist in reality and it is common to encounter different models on different markets within a same country. Most countries choose for a step-by-step approach where the future steps are often only sketched. More models can be developed than can be observed in the real world. It will in all cases be necessary to take account of the specific local situation and aims to design an appropriate model. The development of the required regulation and contracts necessitates specific skills, professional organisations and an appropriate amount of time. This can be quite costly but it is assumed to produce advantages in the longer run. The creation of a level playing field is a requirement for fair competition.@en