From press release:

 

Aucklanders will be able to stay connected on their mobile phones and other devices when they use the City Rail Link (CRL), the country’s first underground railway, next year.

 

City Rail Link Ltd, its main contractor, Link Alliance,  and telecommunications companies One NZ, Spark and 2degrees have begun installing the infrastructure that will bring both 4G and 5G high-speed mobile connectivity throughout the 3.45-kilometre-long CRL tunnels and at the new Te Waihorotiu, Karanga-a-Hape, and Maungawhau Stations.

 

“Installing technology that allows high-speed communications connectivity is an important part of delivering a world class railway for Aucklanders. Not only will passengers get to new places faster, but they will also be able to stay in touch, stream, and access information while underground” says City Rail Link Ltd’s Chief Executive Patrick Brockie.

 

One NZ is leading the installation of the physical infrastructure on behalf of all three network providers, supported by their technology partner Nokia. It is the first time the three mobile operators have collaborated to build a solution of this scale, ensuring continuous mobile coverage in the tunnels across their networks.

 

Besides keeping passengers connected, 5G also plays a vital safety role for the City Rail Link — helping protect people in the event of an underground incident.

 

“Connectivity underground is crucial for real-time train tracking, emergency communications, and integration of CRL with Auckland Transport systems that keep public transport running,” says Auckland Transport Chief Executive Dean Kimpton. “It will help to keep trains and passengers on time and online.”

 

One NZ and CRL Ltd say installing underground mobile infrastructure is a complex technical task, requiring careful coordination with the wider fit outs of the CRL station and tunnel systems.

 

“We're proud to be leading the design and implementation of the mobile network infrastructure for Auckland's underground transport network, helping to deliver a better-connected Aotearoa. Testing is complete, and our teams are now busy underground installing the system that will support modern urban transport and help Kiwis stay connected throughout their journeys,” says Thaigan Govender, One NZ General Manager Mobile Access Network.

 

Although cell coverage above ground is widespread thanks to cell towers, establishing it underground poses significant challenges. Solid materials such as concrete, steel, and earth used to build the CRL make it harder to provide consistent wireless connections.

 

The work involves the installation of a large amount of sophisticated hardware and software – over 350 radio transmitters connected by 74 kilometres of cabling, and 30 kilometres of leaky feeders (cables that transmit radio frequencies) – to ensure mobile coverage throughout the CRL tunnels and stations. Installation will continue into early next year and full coverage is expected when CRL opens in 2026