Semmering railway

The Semmering railway is a railway in Austria. It starts at Gloggnitz and leads over the Semmering to Mürzzuschlag. It was the first mountain railway in Europe built with a standard gauge track. It is commonly called the world's first true mountain railway. This is because of the very difficult terrain and the large altitude difference. It is still fully functional as a part of the South railway.
The Semmering railway was built between 1848 and 1854. There were about 20,000 workers. The director was Carl von Ghega. There are 14 tunnels, 16 viaducts and over 100 curved stone bridges as well as 11 small iron bridges. 
In 1998 the Semmering railway was added to the list of the UNESCO World Heritage sites.