Tallawong Rd, Water Main Adjustments for Sydney Metro Northwest

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Sydney Metro is Australia’s largest public transport infrastructure project – Sydney Metro Northwest, formerly the North West Rail Link, is the first stage of Sydney Metro, and Metro City & Southwest is the second stage.

Sydney Metro Northwest will be the first fully-automated metro rail system in Australia and is on track to open to customers in the first half of 2019. Sydney Metro Northwest will deliver eight new railway stations and 4,000 commuter car parking spaces to Sydney’s growing North West population.

Project Scope

UEA Trenchless was awarded the Tallawong Road water main adjustment project in October 2015, under its Sydney Water W2 supplier listing. The project involves the turnkey asset relocation of the existing mains for the cut and cover rail construction on Sydney Metro Northwest rail project.

UEA Trenchless installed HDPE PN20 pipes, performing five parallel HDD bores through 90mpa Minchinbury sandstone using a Vermeer D300x500 and Vermeer D100x120. The PN20 pipes ranged from 800mm to 280mm and will replace the existing water mains, which are required to be removed to facilitate the installation of the Sydney Metro Rail line. UEA Trenchless is contracted to deliver both the trenchless and trenched components of work.

Techniques Used


  • Utilisation of D300 HDD Rig and D100 HDD Rig
  • Steering Engineer employed to monitor bore accuracy and provide feedback to the drill rig


  • Large excavations in rock to conduct bore tie-ins
  • Conventional trenching works, including significant and detailed anchor/thrust blocks and concrete encasement

The Works

This project presented a number of challenges from the onset, primarily ensuring that the five parallel bores were constructed in a tight 3m by 3m window. Through the skilled and professional operation of the HDD crew, and with the assistance of a Steering Engineer, UEA was able to deliver the trenchless works to specification. UEA Trenchless is currently completing the conventional trenched component of works and is on program to complete these critical works late by June 2016.