“Breakthrough moment” for engineers working on the £642 million Gotthard Base Tunnel is expected to occur this afternoon.

The tunnel is part of the Swiss AlpTransit Project which aims to make railway transport under the Alps more competitive for both passengers and goods and will, when opened to traffic in 2017, knock an hour off the journey from Zurich to Milan.

The tunnel, containing two tunnels with one track each, is 57 kilometres [35.4 miles] long and today, when engineers drill through the last layers of rock connecting the two ends, it will become the longest railway tunnel in the world.

Other, shorter railway tunnels are also planned for under the Alps so that high speed trains from Germany will be able to continue through Italy and a tunnel connecting Lyon with Turin would largely replace the Brenner Road Tunnel from Austria to Italy.

The new railway tunnels, as well as shortening journey times, will also reduce traffic on the congested roads through the Alps.

Have you driven through the Alpine road tunnels?