Start of driving inclined shaft in Ritom

​The TBM is being assembled

The TBM has a diameter of 3.2 metres. The inclined shaft has a gradient of 42% (L = 585m) and 90% (L = 810m) and overcomes 770 metres in height. The start of driving is planned for 03.03.2021. After breakthrough into the shaft head cavern, the TBM will return to the base of the shaft and be dismantled there. As soon as the TBM has left the access gallery, the shaft support will start with the installation and backfilling of the steel armouring.


The excavation work on the Piora apparatus chamber is about 75% complete.

In wintry conditions at 1837 m.a.s.l., the work could be advanced until 18 December 2020. The work in Piora is currently being interrupted during the winter because the amount of snow and the alpine weather make construction work impossible. On 08.02.2021, snow clearance was started again, and construction work is expected to be resumed from the end of February 2021.

​Piotta / CRISA Headquarters Building

The concrete works of the central building are in progress in the area of the turbine shafts. The execution of shell 1 is expected to continue until the end of August 2021.

Piotta / DMDBA equalisation basin

The excavation of the equalisation basin part 1 and the return structure have been completed. Currently, the uphill closure wall and the drainage system are being executed. The execution of the asphalt sealing of the equalisation basin part 1 is planned from April 2021.

Further information on the project can be found on the reference sheet.

Marti Tunnel AG
Seedorffeldstrasse 21
CH-3302 Moosseedorf
+41 31 388 75 10