Norway is building its longest railway tunnel between Oslo Central Station and the city of Ski. This tunnel was conceived for a design speed of 250 km/h.

In order to drastically increase the capacity of the south corridor from Oslo, the Norwegian rail authority Bane NOR is building a 20 km long double-tube railway tunnel that will halve travel time between Oslo and Ski. Passenger and freight trains will travel with a speed of up to 250 km/h.

With rising train velocity, aerodynamic considerations become increasingly important. Amberg Engineering was responsible for the aerodynamic evaluation and optimisation of the planned tunnels. This concerns aerodynamic drag as well as aural passenger comfort and health. The so-called health criterion imposes an upper limit to pressure fluctuations originated by high-speed tunnel transit. 

The challenge in this project stemmed from the heterogenous train park combined with several options for tunnel cross section. This resulted in numerous scenarios to be evaluated. 

Amberg Engineering’s specialists could master this challenge and both comfort and health of passengers traveling on this line can be guaranteed.

Further services provided by Amberg Engineering include tunnel design, including the rescue station in the centre of the tunnel system, ventilation design and support to the development of the intervention strategy.


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