The Republic of Croatia has a favorable geopolitical position, and the port of Rijeka is the most important Croatian port that has great significance for the entire state economy. Since the railway line Rijeka - Zagreb is not functioning at an appropriate level, and the share of goods transported by rail to the rest of Europe is as high as 30%, the construction of a new railway line becomes necessary. The geomorphic specialty of the port of Rijeka, and especially its significance in the corridor for Central Europe, calls for the modernization of the container terminal in Rijeka and the Rijeka - Zagreb railway, so that the goods flows on the Rijeka - Podunavlje route can normally circulate. The theme is initially exhibited through the history of railway traffic, both in the world and in Croatia. The focus is also on the port of Rijeka as well as the connection of the Rijeka - Zagreb railway with important European corridors. Also, the planned projects for the development of the railway infrastructure on this section are presented and the interaction of the railway connection with the development of the port of Rijeka is being considered.