14 European countries signed a declaration calling for implementation of the Baltic-Adriatic Corridor between Gdańsk and Bologna in 2009. Work began in late 2008 on the first phase of the Austrian Koralm Railway between Graz and Klagenfurt, including the long Koralm Tunnel, the largest infrastructure element of the line. It is expected to be operational by 2025. In 2012 construction of the Semmering Base Tunnel started, expected to open in 2027, bypassing the gradients of the Semmering Pass.