Summary of my thesis. Feel free to correct!! This thesis consists of the project of adjustment the infrastructure of the railway line number 7: Klementowice - Miłocin Lubelski to the international requirements. To meet these demands it is necessary to increase the maximum velocity applicable on the section to 160 km/h for passenger trains and to 120 km/h for freight trains. In the beginning of the thesis the analysis of the existing condition on the railway line is presented, including damages of the railroad surface. Furthermore the constructive standards of the railroad surface are discussed, the requirements and the technical conditions containing the guidelines of modernization and railway lines construction in Europe and Poland. In the end of the thesis two modernization options are considered together with their juxtaposition and the cost comparison for each of them. In this paper two modernization options are presented. The first one assumes revitalization of the railroad surface currently existing on the analysed section. The second one based on interference in the current geometrical arrangement, that is, first of all, increase in radiuses of the horizontal and vertical arches. At the end the summarization and analysis of the carried solutions are presented and after, the selection of the best modernization variant has been done. There are four technical drawings of the current state of the railway line and of the proposing solutions attached to the thesis: the longitudinal profile of the railway line section Klementowice – Miłocin Lubelski in the current state (attachment nr 1) and after modernization (attachment nr 2), situational plan in the current state (attachment nr 3) and after modernization (attachment nr 4).