Erkat Transverse Drum Cutters chosen for City Rail Link tunneling project in Auckland, New Zealand

March 2021 – Five Erkat transverse drum cutters have been chosen for New Zealand’s largest ever transport infrastructure project. Supplied by Erkat distributor Digga NZ, the Erkat attachments will be used for the 3.45 km twin-tunnel underground City Rail Link (CRL) now under construction up to 42 meters below Auckland city center. The two larger Erkat drum cutters are currently in operation excavating the tunnel opening. The smaller attachments will be used for wall profiling, excavating service tunnels and other tasks.

New Zealand has a population of around five million. Auckland, home to 1.7 million, is the country’s largest city. Jointly funded by the Government and Auckland Council, the new City Rail Link is estimated to arrive at a total cost of NZD 4.4 billion. The project will transform Auckland’s downtown Britomart Transport Center into a two-way through-station that better connects the Auckland rail network and allows it to more than double its rail capacity. The main CRL works, including stations and tunnels, will be delivered by a consortium of seven companies called the Link Alliance.

Completion and handover of the City Rail Link is scheduled for late 2024. For more detailed information visit:


Digga NZ’s scope of supply

Dean Hewlett, Product Manager, Digga NZ Ltd.: “CRL Link Alliance requested quotations for Erkat transverse drum cutters suitable for 8 ton, 14 ton, 34 ton and 45 ton excavators. We discussed the project application with them and determined that these attachments would be a suitable choice to handle the geological formations they would be working in.”

The transverse drum cutter attachments supplied by Digga to the Alliance were an Erkat ER1500 and ER250, two Erkat ER600’s and an Erkat ER2000-2TU. With the assistance of Digga NZ, the machines were mounted on a Yanmar Vio80 excavator, two Doosan DX140LCR excavators, and Liebherr R924 and R950 tunnel excavators, respectively.

The Erkat ER1500-1X and ER2000-2TU are now being used to excavate and create the opening/starting point for the journey of the 7.15 meter diameter TBM’s (Tunnel Boring Machines). The smaller ER250 and ER600’s will be used for wall profiling, excavating service tunnels and other tasks.

Performing to expectations

Dean Hewlett, Digga NZ: “To date, CRL Link Alliance are extremely satisfied with the performance of the Erkat drum cutters. Digga NZ provided the support they needed during the procurement and mounting of the attachments on the carriers. We have also provided parts and service assistance and will carry out repairs on the machines if required.”

Erkat drum cutters, suitable for a range of jobs

With models suitable for carriers of all weights up to 70 tons, Erkat transverse drum cutters are a productive choice for rock or concrete wall and surface profiling, trenching, soft rock and frozen soil excavation and demolition. All Erkat drum cutters in the range feature integrated 360° hydraulic rotation, allowing optimal precision and precise handling and, in turn, maximum productivity in challenging applications.


An adaptable high torque gear motor gives high efficiency with long motor lifetime, and each unit is equipped with a high load resistant output shaft bearing system with lubrication-free slide ring seal system. Robust spur gears allow optimum energy transmission and reliability and the rugged housings are enhanced by HARDOX wear protection for operation in tough working environments.

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