Breakthrough has been achieved in the 33 kilometer long Koralm Tunnel. Excavation of the tunnel started in 2008 under the Koralpe mountain range of Austria. If you also count the exploratory tunnel, work started not 12 but 18 years ago.

In 2026, when the tunnel is finally operational, it will be the longest railway tunnel in Austria. The south tube of the tunnel was excavated using drill & blast while the north tube has been excavated via a tunnel boring machine called Kora. In addition two tubes are connected to each other via cross service tubes at every 500 meters.

https://www.kleinezeitung.at/service/topeasy/lebenshilfe/5827274/Leichte-Sprache_Durchbruch_Grosser-Tag-fuer-Bauarbeiten-beim