The wide railway universe, with its particular and peculiar characteristics, requires the implementation of criteria to improve the identification and conservation of cultural goods. Recently concepts of authenticity, integrity and cultural significance have been identified as fundamental in the selection of the cultural heritage of humanity. Although we find these concepts being analyzed in theory as independents, through a theoretical-methodological reflection, this PhD research argues that, in practice, they are interconnected, and therefore should be approached together. Following the contemporary theory of conservation, my doctoral research aims at contributing to the conservation of railways’ heritage using this new approach, by proposing new indicators as assessment tools so that conservation institutions will be able to identify railway goods as cultural heritage. The research uses the Railway Complex of Barreiro, in Portugal, as a case study.