Planning the extent of transport services within a selected territory is a topical issue especially in the context of developing integrated transport systems. The objective of this research study is to design a sustainable system of public passenger transport that would be an alternative to expanding individual transport. The implementation of a quality and efficient transport service is a relatively complex process, since, currently, there are no generally applicable principles for its design. This manuscript presents general results of research aimed at solving the problem of transport service within a selected territory issue with a focus on rail transport as an efficient transport system representing a backbone of a transport system. The subject of the investigation is to compile a set of factors affecting the design of the transport concept. The output of the manuscript consists in a proposal of a generally applicable procedure including a calculation of transport potential and characteristics of the inputs. Subsequently, based on the resulting values, it will be possible to determine the extent of the transport services provided by rail transport in any territory, which will contribute to a more efficient and high quality theoretical graph of train running.