Malaysia first made use of the latest technology in tunnel boring to build the dual purpose (roadway and flood control) Smart Tunnel in Kuala Lumpur. Currently, MRT Corp is using the tunnel rigs to build underground rail to connect with the integrated SPAD transport system in the Klang Valley. In other countries longer and complex tunnels have been built of which The Chunnel crossing the English Channel is the most ambitious.
Motorcar tunnels. The longest (24.5km) is at Laerdal, Norway.
Rail and carriage tunnels, Seikan Tunnel, the longest (53.6km).
Boring the tunnels.
Circular drill bit (left) and and drill (right)
One end of a tunnel in use.