The fatigue fracture is one of the most critical failures which may occur on the high speed network because it is undetectable and it has a huge impact on traffic disruption. The contact wire lifespan of a high speed line is estimated at more than 50 years and thus it is necessary to consider the risk of fatigue. The Railway Technical Research Institute in Japan studied this phenomenon for a long time and performed experimental tests. Using these results and by comparing with failures occurred in France, a preliminary analysis is carried out to identify parameters which significantly influence the fatigue phenomenon. This analysis consists in using the numerical software OSCAR© to evaluate the loads, perform a fatigue assessment of the contact wire. The procedure, using a one-dimensional and a three-dimensional model, is described in this article.