25 Euro of Austria 2013 AgNb Proof - Tunnel Construction

Opened in 1848, the vertex tunnel of the Semmering railway was the world’s first alpine tunnel. The ‘New Austrian Tunnelling Method’, which uses the geographical stress of surrounding rock to strengthen a tunnel, was developed from 1957 to 1965 and has since done a great deal to revolutionise tunnel construction around the world. A present-day tunnel boring machine features in the niobium side of the coin’s obverse, its rotating motion symbolised by three arrows. The obverse’s outer silver ring shows the mountains through which the machine pierces. The coins reverse makes excellent use of the niobium pill to show one of the many road tunnels that pepper Austria’s alpine landscape today, while a tunnel worker uses a pneumatic drill to loosen rock in the silver ring alongside the word “Tunnelbau” (tunnel construction).