The preliminary design of the project consists in the upgrading of the second track between Hrvatski Leskovac and Karlovac stations, for a total length of circa 45km. The railway line will be double-tracked and electrified on the whole section with a design speed of 160 km/h for passenger trains. The project is part of the corridor V-b that connects Rijeka Port to Zagabria and Budapest. Coding performed the design of the railway alignment, of minor works and of the architectural and structural of all the 6 stations.