On 19/04/2021 - about one month after construction works started, they broke through. The works were below the riverbed of the Isarco river for the future Brenner Base Tunnel railway. Excavation below the river was only possible after freezing the soil with liquid nitrogen and then maintaining low temperatures by circulating brine.  

Works were carried out with a percussion hammer, which breaks up the soil reaching a 1.5 m/day average daily advancement. After the excavation works have been completed, the next step will be the final concrete lining of the tunnel. During 2020 one of the other tunnels was excavated using soil consolidation and two other tunnels are yet to be dug using the same method. For further information please click here, at/16 and it/103 for the tunnelbuilder archive and also visit https://www.bbt-se.com/en.  16/21.