Rail officials have procured half the cost of a planned $8.1-billion tunneling project in Melbourne, Australia, but the 9-kilometer-long tunnel-boring plan, which is slated to begin in 2018, still faces political hurdles.
The Melbourne Metro Rail Authority (MMRA) has opted for tunnel-boring machines to excavate twin tunnels underneath the Yarra River, which poses “a number of engineering challenges, including navigating complex geological and hydrological conditions, the need to protect the environmental significance of the river and limited space on either side of the river for construction,” says MMRA Chief Executive Officer Evan Tattersall.