Narromine to Narrabri section update – September 2024
Over the last couple of months members of our Stakeholder Engagement team have been speaking with impacted landowners about fieldwork we need to complete and how best to arrange access to their properties.
September 26, 2024
We’ve progressed with our schedule and want to thank all landowners who have collaborated with us.
Upcoming fieldwork will include geotechnical investigations for borrow pit sites, land surveys and measurements, ecology and environmental surveys.
Geotechnical investigations resume between Narromine and Gilgandra
Plans are underway to resume geotechnical investigations between Narromine and Gilgandra by the end of October. We are hoping to complete work across a total of 14 sites identified as potential borrow pits.
We will notify the local community with exact work dates and more details of the scope in a few weeks’ time.
What are borrow pits?
Borrow pits are small quarries that provide earth materials (soil, rock and gravel) to be used in construction. The new construction ‘fill’ is used to build track embankments or for earthworks around new bridge structures, to ensure the track remains as flat as possible across varied terrain.
As part of the investigations, crews will drill boreholes as deep as 15m and dig test pits as deep as 5m to test soil composition. The soil samples collected are sent to a laboratory for detailed analysis.
The number of boreholes and test pits dug at each site will depend on the estimated size of each proposed borrow pit, and the type of construction material we are hoping to extract.
Inland Rail has been investigating potential borrow pit locations along the Narromine to Narrabri (N2N) section since 2019. Where ground conditions potentially meet our technical requirements, we work closely with landowners to discuss whether a commercial arrangement to obtain earth materials is agreeable to both parties.
Inland Rail will also be required to meet relevant environmental regulations around the borrow pits, including consideration of traffic impacts, rehabilitation and other factors.
Refining the design – what do we mean by that?
One of the most important tasks we’ve had to carry out since the Inland Rail review was published in April last year has been to gain more certainty about the project’s scope and cost. This year we’ve been speaking with more landowners about upcoming fieldwork we need to complete to help us refine the project’s design to better understand the scope of the Narromine to Narrabri section.
Refining the design means reviewing the engineering assumptions and decisions made so far using new data and information. It involves creating and testing models of the railway and supporting infrastructure and updating them when new detail about the environment emerges. Usually this is based on ground surveys and data gathered in the exact locations where Inland Rail will be built.
For example, through a review of publicly available data and consultation with engineering experts we have proposed a bridge over a creek. The design of the bridge will be refined, and further decisions made about specific elements (such as its length, number of supporting piers, and depth of supporting piers) once we have completed a ground survey of the area including a hydrology review and geotechnical investigations.
Close consultation and input from impacted landowners, councils and local agencies informs design decisions at all stages of the design process.
So Inland Rail can finalise its designs for the Narromine to Narrabri section, we need the continued permission of landowners to access their properties using land access agreements. Thank you to the many landowners who have recently collaborated with us to enable these essential works.
Image caption: A visualisation of an embankment leading to an overbridge over Yarrie Lake Road, Narrabri.
Questions?
For more information about the Narromine to Narrabri section of Inland Rail, phone: 1800 732 761 or email inlandrailnsw@inlandrail.com.au.
