Bohinj railway line runs from Jesenice to Trieste. Its construction began in the Gorenjska region in 1890 and was completed in 1906. Construction of the railway was very challenging because the Baska valley is very narrow. Specialty of the railway are tunnels, galleries, bridges and viaducts. The longest and most powerful viaduct is crossing the road and the river Idrijca at Bača pri Modreju. At the end of the viaduct, the Austrians built a fort for defense purposes. After the First World War it was used by the Italian army for living spaces and a warehouse for weapons.