site.btaDecember 21, 1952: Sub-Balkan Railway Line Unveiled

On December 21, 1952, the sub-Balkan Railway line was unveiled in Bulgaria, connecting the capital with the coastal city of Burgas.

For a long time, studies were made for a faster transport connection between Sofia and Burgas with a route running below the Balkan Range. First it was decided to build a route between Sliven and Zimnitsa station, located on the already built railway link between Yambol and Burgas. The section Sliven - Zimnitsa was completed and put into operation on May 23, 1907.

The question of a study for the construction of the railway was raised in 1909 during the regular session of the National Assembly. Funds were also allocated, and work on the survey of the line from Sofia to Sliven began the same year. economic and historical factors delayed the completion of the route from Sliven via Karlovo to Sofia. 

Individual sections were completed between 1921 to 1931, such as the links between Tulovo and Kazanlak,  Dubovo and Tvarditsa, and Tvarditsa and Sliven. Despite the great importance of the railway, its complete construction was hampered by the study of the passage of the three watersheds that connect the Balkan Range and Sredna Gora. The most complicated section from an engineering point of view was between Makotsevo and Sopot due to the complex mountain topography. The survey services made repeated changes to the already surveyed routes and searched for options and solutions to overcome them for nearly 30 years.

Eventually, the sub-Balkan railway line was completed in 1952. The first train crossed the route on September 7, 1952, and the grand opening of the line took place on December 21, 1952.