During an inspection in 2006, severe damages were discovered in several areas of the existing tunnel, with the urgency of a refurbishment in up-coming years. Additionally, the tunnel was not meeting the modern requirements for either the clearance envelope (load gauge) nor for safety. 

For these reasons, a new single-track tunnel will be built parallel to the existing one. The old tunnel will be used as safety tunnel.

Project description

  • After the tunnel inspection in the year 2006 the refurbishment of several areas of the existing tunnel (5’865m) and safety improvement were decided.
  • The final decision was to build a new tunnel parallel to the existing one. After refurbishment of the old tunnel it will be used as an emergency escape tunnel.
  • Both tunnels will be connected by cross-passages approx. every 450m.
  • The new tunnel will have a single-shell shotcrete lining, with double-shell lining near portal areas.
  • Length of new tunnel will be 5’855m.
  • Difficult geological conditions and water inflow at portal areas. Greywacke formation of 100m thickness with “swimming mountain”
  • Mountainous climatic conditions at 1‘800m a.sl., cramped conditions at installation areas, complex logistic conditions
  • Conservation of environment and heritage, ensuring max. work safety at the same time
  • Overall project management
  • Progress, cost and quality control 

Project Details

Merge between the old and the new tunnel

  • Narrow gauge single track tunnel
  • Cross-section 40m2
  • Double shell lining in portal area and in wet areas
  • Single shell lining for the remaining tunnel
  • Fixed carriageway and power rail catenary

Refurbishment work inside the tunnel

  • Refurbishment of the old tunnel in accordance to new safety requirements
  • Securing of the tunnel using shotcrete, mortar and anchoring for the desired new safety functionality 

Albula, UNESCO world heritage

  • Cross passages at 435 – 456m intervals between new tunnel and old tunnel (safety tunnel)
  • Technical infrastructure in separate caverns within the cross passages 
  • Ventilation of safety tunnel with overpressure