A Chinese-built earth pressure balance tunnel boring machine recently arrived in New Zealand, destined for Auckland’s City Rail Link project. Due for completion in 2024, the $2.8-billion project has struggled with a major cost hike and bankruptcy of a leading contractor.

The Herrenknecht 7.18 m dia TBM from Guangzhou, China, will be assembled at Auckland’s existing Mount Eden station and drive 3.2 km of twin tunnels. The 3.45 km of railway will connect the existing Britomart and Mount Eden stations.

The tunnels and three new underground stations form part of a $1.1-billion contract between City Rail Link Ltd. and Link Alliance, which includes Vinci Construction Grands Projets S.A.S., Downer NZ Ltd., Soletanche Bachy International NZ Ltd., WSP Opus (NZ) Ltd., AECOM New Zealand Ltd. and Tonkin + Taylor Ltd.

Estimated at $2.3 billion in 2014, the railroad’s budget was raised by 30% in April 2019 partly influenced by a regional construction boom, according to City Rail Link Ltd. CEO Sean Sweeney.

“No-one could have foreseen the competitive pressures that have occurred in the construction industry,” he noted. The decision to extend stations for longer trains also boosted costs.

Link Alliance is delivering design and construction of underground work and railroad systems  The team is working in alliance with the owner following an outline design by a group of firms led by Aurecon Group.

The team contract, signed in July 2019, was originally intended to cover civil construction only. But during the bidding phase, the consortium that was picked to deliver railroad systems, including track, lost a key member to bankruptcy. In late 2018 RCR Infrastructure (NZ) Ltd., went into court protection. To avoid losing time, the owner allowed the weakened consortium to continue with the design.

At the time, there were still two bidders in the running for the civil work. Link Alliance emerged as preferred bidder in April 2019.

Its contract also included about $50 million of early preparatory work to save time. City Rail Link Ltd. had also awarded a series of other preparatory contracts covering shallower tunnel approaches to the new line.