Alps
The region is serviced by 4,200 km (2,600 mi) of roads used by 6 million vehicles. Train travel is well established in the Alps, with, for instance 120 km (75 mi) of track for every 1,000 km2 (390 sq mi) in a country such as Switzerland. Most of Europe's highest railways are located there. Moreover, plans are underway to build a 57 km (35 mi)-long sub-alpine tunnel connecting the older Lotschberg and Gotthard tunnels built in the 19th century.
Where are most of Europe's highest railways located? 
Switzerland
Train travel is well established in the Alps, with, for instance 120 km (75 mi) of track for every 1,000 km2 (390 sq mi) in a country such as Switzerland.
Europe's highest railways