The north portal of the Lötschberg base tunnel opens at Frutigen, where trains travel at 200-250 km/h over a distance of almost 35km to reach Rarogne in Valais.

It's a friendly, unassuming village that's not very well known: it's part of the Frutigen-Adelboden tourist destination, but of course it remains somewhat in the shadow of the mountain resort 1000m higher up.

The big attraction here is the Tropenhaus Frutigen (Tropic House), which harnesses the tunnel's geothermal energy.

The Lötschberg base tunnel produces 100 litres of hot water per second, at around 20°C. This heat energy is used by the Tropic House to heat a greenhouse and a sturgeon farm where caviar and exotic fruits are produced.

There are exhibitions on the tunnel and the mountains, energy issues, fish farming, food and sustainable development. And, of course, there's a restaurant where you can taste dishes based on sturgeon and fruit produced on site!

Inaugurated in 2007, the Lötschberg base tunnel reinforces the old tunnel, almost 15km long, which links Kandersteg (higher up in the same valley) to Goppenstein in the Lötschental (Valais). Inaugurated in 1913, the old tunnel is of course still used: it is the one that provides piggyback transport, making it possible to cross the Alps by car even in the middle of winter.

Useful links

Swiss Canton of Bern (iSwitzerland Guide) - Wikipedia