A Bulgarian joint venture PSVT build it
https://constructionreviewonline.com/biggest-projects/shipka-tunnel-project-implementation-in-bulgaria-begins/
The PSVT consortium was chosen for the Shipka Peak Tunnel project as part of the Gabrovo City bypass near Yantra River.
https://constructionreviewonline.com/biggest-projects/shipka-tunnel-project-implementation-in-bulgaria-begins/
Shipka Tunnel Project Implementation in Bulgaria Begins
constructionreviewonline.comThe PSVT consortium was chosen for the Shipka Peak Tunnel project as part of the Gabrovo City bypass near Yantra River.