Albula Tranche 103 is part of the new Albula II tunnel construction project, for the Rhaetian Railway (Rhb). The main project involves the construction of a railway tunnel with a length of about 6 km, with the modernization of the Preda and Spinas stations at the two portals.
Tranche 103, in particular, required the securing of the original "Albula I" tunnel, which is a UNESCO site and over a century old. This involved a static restoration of the structure using stonework and some Shotcrete. The project also included the excavation (through blasting) of the entrances to the 12 cross passages that will connect the "Albula I" tunnel with the new Albula II tunnel. Furthermore, piping for industrial and fire prevention water was laid out along the whole route.
Rhb approved an extension of the contract, which provided for the expansion of the existing survey cave along the axis of the future Albula II tunnel for a total of 2500 m3 of blasting excavation.
All construction activities were carried out with the aid of specially equipped trains during night hours, without interruption of services.