The thesis deals with a sustainable planning of railway infrastructure and sustainable development of transport by introducing new options of connectivity towns with the railway line, with a focus on tourism development of these areas. The first part of the thesis presents the importance of rail transport and rail infrastructure and the importance of sustainable transport and sustainable mobility. Because Slovenia is a Member State of the European Union, the thesis deals with the sustainable development of transport in Europe as a single European transport area. It also presents examples of sustainable planning railway infrastructure around the world. The following thesis describes the existing railway infrastructure in the area north-west of Slovenia, in detail railway line Ljubljana – Jesenice and Bohinj railway line. Railways are basic for sustainable design of the proposed new links Lesce – Bohinjska Bistrica and Most na Soči – Tolmin – Kobarid – Bovec. Because listed cities are often tourist destination, the thesis presents the integration of railway and tourism, the importance of building railway infrastructure in tourist areas, sustainable and green tourism and the characteristics of railway passenger traffic. In the second or the practical part of the thesis are presented the theoretical foundations and calculations of geometric elements of the proposed railways Lesce – Bohinjska Bistrica and Most na Soči – Tolmin – Kobarid – Bovec. Railways are designed by using the software CGS Ferrovia. At the end of the thesis are described all the proposed variants of both railways as well as technical and environmental possibilities of railways placement in space.