A rail project in Slovenia has met some obstacles that are intriguing designers and engineers as it drives tunnels through karst landscapes.
The Divaca-Koper railway connection is a project to create a modern, reliable link between Koper cargo port on the Adriatic Sea and the wider European rail network.
Part of the route passes through a type of topography known as karst, which is characterised by sinkholes and caves. The route has seven tunnels and karstologists have discovered 88 caves that affect them. One of the tunnels, measuring 6km, will need five cave bridges measuring between 25m and 40m. The freight trains using the railway will weigh up to 2,500t, and designers are looking for solutions that will be stable and safe in the long term.
The underground bridges will be a first for Slovenia, and the designers are working with structures that will lie beneath the tunnel pipe.
