Theoretical and experimental study of congestion phenomena on an urban railway network.

Summary Over the past twenty years, public transportation issues in the Paris region have become a major concern. The French national railway company, which operates most of the rail network in this region, plays a central role in the organization of transportation. However, in contrast to the expectations placed on this sector, rail traffic is experiencing a number of dysfunctions. This thesis is part of a global approach to question the principles of rail operations in dense areas, and provides a new perspective on the origin of delays affecting trains. A simple model is proposed to study rail traffic congestion under the influence of random disturbances. Inspired by road traffic tools and especially the fundamental network diagram, we define for railways the fundamental railroad line diagram which allows to represent the flow as a function of the concentration on a portion of railroad line. This tool is then used to compare the results of our model to a data set measured on two railway lines in the Paris area. This comparison shows that our model allows to qualitatively reproduce the traffic congestion phenomena observed on real cases.