Gotthard tunnel: World's longest and deepest rail tunnel opens in Switzerland under Swiss Alps

Yodeling and a triumphant Alpine horn heralded the inauguration Wednesday of the longest, deepest railway tunnel ever constructed — a feat of engineering that will slash journey times across Europe.

The Gotthard Base Tunnel under Switzerland's Alps has taken 17 years and cost about $12 billion to construct and removes one of Europe's most stubborn natural barriers to trade and tourism: the lack of a fast route through the mountain range at the crossroads of four countries.

The 57 km (35 mile) twin-bore Gotthard base tunnel will provide a high-speed rail link under the Swiss Alps between northern and southern Europe.

Switzerland says it will revolutionise European freight transport.

Goods currently carried on the route by a million lorries a year will go by train instead.

The tunnel has overtaken Japan's 53.9 km Seikan rail tunnel as the longest in the world and pushed the 50.5 km Channel Tunnel linking the UK and France into third place.

Once the route for commercial service opens in December, it will take up to 260 freight trains and 65 passenger trains per day — reducing the number of cars and trucks clogging the roads between northern and southern Europe.