Twin tunnels, single bores and megabores – Local subway planners face choices on what will work best for new lines

Each new subway tunnel is as unique as its surrounding neighbourhood and geology. While six-metre, twin tunnels were once considered standard, more recent technology has made larger, single tunnels possible. This article reviews the different sizes of tunnels and the factors that go into choosing one. Let’s get out the tape measures - the really … Continue reading Twin tunnels, single bores and megabores – Local subway planners face choices on what will work best for new lines