The 6,5m Tunnel Boring Machine has already excavated the 3250 meters of the Sarneraa valley tunnel. The Herrenknecht has another 3250 meters to go to complete the 6500 meters long tunnel. The contractor of the project is HWS Marti consortium. The TBM had been launched at Sachseln in mid-January 2021.

Luzerner Zeitung reports that currently the TBM is boring at 80 meters of dept to the west of the village of Kerns. According to Luzerner Zeitung, the soft rock formation allows advance rates of up to 40 metres a day.

I believe this TBM had been previously used for the tunnel of the Linth Limmern power plant in the canton of Glarus.  It has been refurboshed by the Marti Tunnel's Marti Technik team with the cutterhead coming from the TBM supplier.

https://www.luzernerzeitung.ch/zentralschweiz/obwalden/meilenstein-die-haelfte-des-stollens-im-sarneraatal-ist-ausgebrochen-ld.2248821