As everyone who has had a new house built knows, building is never straightforward, costs are not always predictable. Headaches can cloud excitement and delays can seem interminable. The Auckland CBD is in that phase of development now. This week our series on Auckland's big projects is checking progress on a number of major projects that together will shape the city well into this century.

It started yesterday with the City Rail Link, the project that has put most of Albert St out of commission for the past three years for the cut and cover phase of the underground railway. The major part of the project, a tunnel from there to Mt Eden with stations under the civic centre and deep under Karangahape Rd, has yet to happen. And yesterday the project's latest chief executive, Sean Sweeney, candidly told us the tunnel will be the easy part.

The hardest part, possibly adding more time and costs than yet estimated, may be fitting it out with control systems railways require.


Aucklanders remember the last major transport link built, the Waterview road tunnel, and the delay in its opening while signals and equipment were tested for safety in all conditions. Sweeney said the rail link is far more complicated because New Zealand has never built an underground rail system. It will need to be compatible with systems on the surface lines which, as we well know, are scarcely state of the art.

Sweeney cited London's latest underground line, Crossrail, which appeared to be completed but end-stage problems have added three years and $5 billion to the project. The Government and the Auckland Council are sharing the cost of the City Rail Link and have no firm estimate of the final cost. But once it opens it will give Auckland a central rail circuit allowing trains to run more frequently on the lines to the east, south and west of the region.

Today the series checks on progress with the international convention centre, which has been exhibit A for the problems facing the construction companies when there is a shortage of skilled trades people in a building boom. It is costing Fletcher Building twice as much as it estimated when it bid for the work. Little wonder it's behind schedule and SkyCity has had to turn away its initial bookings.

But when it opens, the entertainment and conference facilities under the Sky Tower will be greatly enhanced, the new conference centre opening to the streets on four sides, its north side adjoining a new 300-room, five-star hotel with a lane of shops and cafes between them. Inside the centre the ground floor will be an exhibition space five times larger than any existing exhibition centre in the country, and above it will be the 3000-seat convention centre, New Zealand's largest.

Over the rest of the week we will be looking at redevelopments of Newmarket, Auckland International Airport, Commercial Bay and the waterfront. Not all of these will be finished by 2021 when Auckland hosts the America's Cup and Apec but the convention centre, Commercial Bay and the waterfront will want to be ready by then. A revitalised central city should be worth the wait.