This work is part of contractual collaborations and aims to develop calculation tools to optimize the maintenance of railways. These tools are based on analytical and numerical models which are coupled with measurements carried out on the track and allow, for example, the use and interpretation of the data provided by “Smart Sleepers”, sleepers developed by the Sateba company, in order to extract relevant indicators concerning the behavior of the sleeper on the track and the overall development of the track superstructure. Another example concerns the work carried out within the framework of the Research Chair linking the École des Ponts ParisTech and the company Eurotunnel which made it possible to carry out a system of automatic and rapid measurements of the level of damage to the track blocks (device COBRA). The measurement principle gives rise to the filing of a joint patent between Eurotunnel and ENPC. The damage levels of the blocks are also used as input data to calculate the dynamic response of the track and in particular the reaction forces on the blocks as well as their displacements according to the mechanical characteristics of the track and the condition. of real degradation of the blocks.