Marmaray tunnel project in Istanbul will be first railway connection between Europe and Asia . The new line is expected to open by 2022, but the Turkish government has said it could take up to 30 years for construction of a second tunnel. Tunnel construction has been delayed by discovery of ancient artifacts . The 76-kilometer ( 47.2-mile ) Seismic activity also a consideration for contractors who have fitted `` flexible joints '' in the tunnel .
Marmaray tunnel project in Istanbul will be first railway connection between Europe and Asia . The new line is expected to open by 2022, but the Turkish government has said it could take up to 30 years for construction of a second tunnel. Tunnel construction has been delayed by discovery of ancient artifacts . Seismic activity also a consideration for contractors who have fitted `` flexible joints '' in the tunnel .