In this thesis, an analysis of the key factors for the competitiveness of the Una railway as the shortest route in the transport of goods and passengers between the north and the south of Croatia is carried out, as a result of the assumed renovation and modernization. Considering the key role of railroads in the distribution of goods in the entire logistics chain and especially in seaports, it is necessary to study the performance of individual railroads in order to optimize costs and increase traffic. The very problem of the operation of the Central Dalmatian ports of Split, Zadar and Šibenik is reflected in the insufficient condition of the existing railroad network, i.e. inactive (Unska railroad) or unsatisfactory (Lička railroad) railroad lines, which significantly increases transport costs and affects the profitability of terminal operators, limits the port hinterland and also prevents the affirmation and perspective of the development of seaports in accordance with the available resource base. Accordingly, the objective of the study is to determine the competitiveness of the Una railway in comparison with selected railway lines in Croatia, under the assumption of planned revitalization, which includes the electrification of the Una railway, and to study the impact of renovation and modernization on the traffic of the Central Dalmatian ports. Using the method of calculation of transport costs (primarily fuel costs) and distance, an analysis of the competitiveness of the Una railway in comparison with selected railroad lines was carried out, along with the projection of the distribution of available freight manifested as a potential increase in the traffic of the ports of Split, Zadar and Šibenik due to the investments made. The results of the study indicate a significant reduction in transport costs (fuel) due to electrification and, analogously, combined investments in electrification and renovation of the Una railway, compared to the observed railroad lines, which have a positive impact on the increase in traffic in the Central Dalmatian ports. The revitalization of the Una railroad indicates the potential to open new markets, i.e. increase the competitiveness of seaports, strengthen the economy of the Republic of Croatia and achieve numerous economic, social and environmental benefits.