Can the construction of a big railway infrastructure become the occasion for (re)structuring the territory passed through? This is the base question of the reflection developed in this manuscript. More precisely, the thesis that we propose may be reformulated as follows: the realization of a big infrastructure (in our case the design of the high-speed railway between Lyon, Turin and Milan) can be the occasion to give the interested territory a more coherent structure by approaching the territorial planning in an inter-scalar and inter-disciplinary way. The analysis of the state of the art of the subjects of the high speed railway and of its territorial context may evidence, from time to time, one or another of the scientific domains that dealt with this topic (economy, geography, social and human sciences, etc.). This thesis tries to intersect multiple disciplines, but approaching the matter from a different point of view: that of urban and territorial planning. Indeed, the themes treated by the transportation geography do not seem able to explain sufficiently well the interactions between infrastructure and territory at all the different scales. By analyzing plans and projects as well as some « design experiments » elaborated with a research-by-design approach, we try to discuss in this manuscript the points of convergence between the domain of the railway transports and that of the sustainable planning of the territory and of the city.
