TBM Ida has completed the excavation of the 8.4 km H41 Sill Gorge-Pfons section of the Brenner Base Tunnel, reaching its destination in the municipality of Navis (Wipptal), near an existing auxiliary tunnel called Iris, bordering the H53 Pfons-Brenner construction section. In modern tunnel construction, the auxiliary access tunnel is an important complementary measure to support the advancement of the main tunnel and to secure the affected section of the tunnel in advance. 

The TBM Ida - diameter 10.4 m, length 160 m and weight 2,420 t - started in June 2023 from Ahrental heading south along the west line tunnel. The TBM successfully completed the first excavation of a main tunnel on the Austrian side of the project, after passing through very complex areas, such as the Viggartal, Walzn and Werner geological fault zones, the latter approximately 35 m long. 

The TBM was christened in 2023 by the children of the Navis primary school with the name Ida, in honour of a heifer that lives on the farm of one of the pupils. The name is synonymous with diligence and hard work. The children accompanied “their Ida” throughout the project. At the end, they were even able to personalise one of the last segments, prefabricated concrete elements used to line the tunnel walls. 

The east line tunnel is scheduled for completion in autumn 2025 with the arrival of the TBM Lilia, Ida's twin. With this new milestone, all mechanised excavation work at the H41 Sill Gorge-Pfons construction site will have been completed. 

Excavation work continues in a southern direction. Attention is now focused on the exploratory tunnel, where the first cross-border underground connection between Italy and Austria will be celebrated on 18 September: a historic milestone for European mobility.

For further information on the project click here, at/16 and it/103 for the tunnelbuilder archive and also visit https://www.bbt-se.com. 35/25.