The Septemvri-Dobrinishte narrow-gauge railway line – a unique project for Balkans.

Abstract The first section of the narrow-gauge railway line Septemvri-Dobrinishte was put into operation in distant 1926, and last sixth stage it completed 1945. It is single line, non-electrified, with a track gauge 760mm, which makes unique for Bulgaria Balkans. Apart from its gauge, impresses spiral ascents, maximum longitudinal slopes - up to 32 ‰, minimum radii horizontal curves 50m highest station on Balkan Peninsula, Avramovo 1267.4m above sea level. Within total length 125 km, 35 tunnels, 23 bridges, retaining walls numerous culverts have been built. article presents current state major engineering facilities along bridges as well superstructure railway. Its technical characteristics, achievement, both terms transport structural construction general, are also commented.