Swiss tunnels

Construction on the Swiss underground cargo tunnel is about to start.

The first 70-km section is expected to cost about $3 billion (presumably USD). And it's all being covered by the private sector. 

Would the all-up consenting costs on something like that in NZ be less than $3 billion, before they broke ground?

Freight honestly seems like a much better use of small-scale underground transportation systems than passenger services, which have been the focus of a lot of recent speculation. Freight tunnels can be smaller and can operate at slower speeds than would be demanded by passengers, and since the entire system is autonomous, comfort (and to some extent safety) can be less of a focus.

The cost (to be covered entirely by the private sector) has increased from the initial 2016 estimate of $3.5 billion—CST is now estimated to cost between $30 and $35 billion for the full 500-kilometer network, although about $3 billion should be sufficient for the first phase, a 70-km section with 10 hubs that connects Zurich with a logistics center in Härkingen-Niederbipp to the west. The Swiss seem mostly unfazed by the scale of the project, and still consider it to be a good long-term investment. CST has partnered with a bunch of large Swiss logistics companies and retailers who see this solution as a complement to existing road and rail infrastructure. The entire project will run on renewable energy, and CST expects the amount of heavy trucks on roads to be reduced by up to 40 percent as its underground vehicles take over transport.