In the context of a collaborative project environment, multiple stakeholders have come together to work on improving the existing East-West connection between Toulouse and Saint-Jory. Project partners include Toulouse Métropole, SNCF Réseau, the Occitanie Region, the municipalities of Saint Jory, Lespinasse, Fenouillet, Saint Alban, Aucamville, and Toulouse, as well as Tisséo Collectivités and Tisséo Ingénierie. The project involves widening the existing infrastructure over a 20 km section, which includes 8 sections of railway bridges between Toulouse and Saint Jory. The primary objective is to accommodate the new TGV line while enhancing cycling and pedestrian connections and public transportation. To achieve this goal, several missions have been defined, including the drafting of a detailed program regarding the impacted structures. The selected engineering firm will be responsible for: Proposing multiple scenarios for the development of the structures and comparing them by conducting multi-criteria analyses of these solutions, taking into account technical quality for users, long-term adaptability, cost, construction method, risks, schedule, etc. Specifying the nature of future structures or modifications to existing structures. Specifying the functionalities of each structure (number of lanes, traffic load capacity, dimensions, active modes, etc.). Detailing the profiles of the structures with cross-sections and detailed plans. Specifying the construction methods of these structures and the associated phasing. Specifying the cost, schedule, and phasing (studies/construction) while considering interfaces with railway works. In summary, this project aims to enhance the existing infrastructure to accommodate the new TGV line between Toulouse and Saint Jory, while strengthening connections between different modes of transportation for more sustainable and integrated mobility in the region.