Basic infrastructure for the Belchen tunnel

Arnold AG performed extensive infrastructure work for the Belchen tunnel. This involved laying 265 kilometres of pipes and 25 kilometres of cable and installing nearly 600 lights.

In the A2 section of the tunnel, which connects the cantons of Basel-Landschaft and Solothurn, a new tunnel was built west of the two existing tunnels from 2018 to 2020. This tunnel will serve as an alternative route when one of the existing tunnels is closed for repair work. Extensive maintenance work on the two ageing double-track tunnels is scheduled to start in 2021/2022.

Our tasks

  • Construction of the basic infrastructure
  • Installation of the operations and safety systems
  • Ensuring the provision of power

Facts & Figures



Construction type

Traffic and tunnel systems

Contruction style

New construction/installation



Carried work

Infrastructure work in the Belchen tunnel

Project manager

Michel Petitat


Federal Roads Office (FEDRO)

Project planning as a success factor

Arnold was awarded the public tender for lot 72 to build the basic infrastructure. The other lots for which Arnold submitted bids – two in total – involved operations and safety systems and the energy supply for the Chiasso tube. As the tunnel involved new construction, there was no traffic while the work was performed. However, the logistics of a project of this size are complex and required meticulous planning to ensure efficient implementation in the period from 2019 to 2020. Internal workshops were used to develop a plan for efficient implementation of the project as well as detailed resource planning. Safety briefings and rules for working at the site were also developed to ensure smooth workflows. Other companies were involved in the project alongside Arnold: Kummler+Matter AG, Baumeler AG and Arge AKB.


Facts & figures for the basic infrastructure for the Belchen tunnel and lot 72:

  • Project perimeter extended over 35-37 km
  • Volume of CHF 6.7 million (Arnold share: CHF 5.35 million)
  • A total of 25 km of cable trays were laid
  • 75 km of pipe systems for fibre optic and medium-voltage cable networks
  • 190 km of pipe systems for low-voltage cable networks and earthing systems
  • 1,700 fire protection plugs to encase the cable conduits
  • Construction of provisional structures beyond the four central control rooms
  • 360 lights for lighting installation in the service duct
  • 160 lights in the exhaust tunnel
  • 75 lights in the 11 cross connections
  • Ensuring the provision of low-voltage electricity for construction from the power distribution stations
  • Cable networks in the service duct for subcontractors

Lots 71 and 11c included the fibre optic cable networks for the operations and safety systems and the low- and medium-voltage switchgears in all transformer stations for the power supply for the Chiasso road tunnel.