The analysis covers the organization of economic activities and how the supply of transportation systems influences the definition of markets. From a spatial perspective, competition and collusion in a high-speed railway (HSR) based network are examined at three levels: (a) the chain of regions served; (b) the chain of cities (railway stations) served; (c) the (chain of) transportation modes involved. Finally, the theoretical part of the analysis looks at the strategic importance of a sequential implementation of network links. The empirical part addresses three cases of peripheries with distinctly different characteristics. It shows that the arguments developed in the first part provide a solid approach to solve the problems leading to different configurations of the recommended system.