Fragile Territories and Secondary Railways—Territorial Dynamics and Innovative Perspectives: The Case of the Reactivation of the Civitavecchia Capranica Orte Railway

The relationship between infrastructure and territory is particularly significant in fragile areas affected by declining accessibility, depopulation, and increasing exposure to environmental and socio-economic risks. In Italy, “Inner Areas” exemplify these dynamics, although they are historically connected to an extensive network of secondary railways originally developed precisely to ensure territorial cohesion. This study adopts a mixed-methods case-study approach to develop an integrated methodological framework for the regeneration of fragile territories through the reactivation of disused railway infrastructure. Combining spatial and mobility planning within a multiscalar perspective, the framework is applied to the Civitavecchia–Capranica–Orte railway corridor and is structured around territorial diagnosis, an Integrated Territorial Masterplan, local Integrated Programmes, and an Axis Contract as an innovative multilevel governance mechanism. The findings show the potential role of secondary railways as territorial backbones within integrated strategies aimed at improving accessibility, supporting sustainable mobility, and promoting long-term territorial regeneration. The proposed framework illustrates how integrated spatial and mobility planning, supported by multilevel governance, can bring together mobility, public services, environmental systems, and local development strategies. The study contributes a transferable methodological framework for the regeneration of fragile territories, highlighting how secondary railways can act as enabling territorial infrastructures within broader long-term integrated territorial strategies based on accessibility, the right to mobility, and institutional cooperation.