Tunnel Talk has some interesting details see:
http://www.tunneltalk.com/New-Zealand-Aug11-Award-of-the-Waterview-Project-in-Auckland.php
and scroll down to paragraphs Tunnel Specs and Tunnel Design. The Waterview machine is a big one by world standards, rail tunnels are smaller. This TBM will bore south to north for one set of lanes, be disassembled and rebuilt facing the other direction, then bore north to south for the other lanes. Rather disappointing as two in a race would be much more fun, it is a westie highway after all.