What are the two key risks to New Zealand's biggest infrastructure project, the $4.4 billion City Rail Link? When will the first tunnels be bored underground from Mt Eden? What stage is the preferred bidder at? In the first of a two-part series Anne Gibson looks at the next most crucial phase of the project.

A giant tunnel-boring machine able to hollow out two separate 7m diameter passages will be shipped to New Zealand soon for work on the CRL passages in Auckland.

With the catchcry of "getting Auckland's heart pumping", the Link Alliance for the crucial C3 or tunnel/station