Client: John Holland

Project: Narrandera to Yanco Cutting and Embankment Works, Narrandera NSW

Barnson’s Role: Surveying, geotechnical, and civil design

Time frame: Project planning carried out in 2014, with works completed in April 2015

Two rail line cuttings between Narrandera and Yanco, on the Junee to Yanco rail corridor were presenting a challenge to John Holland. Poor drainage within the cuttings was causing formation issues, and making it difficult to access the sites to perform routine maintenance. There was evidence of sink holes and blowouts, and a significant amount of rock needed removing. There was also the potential need for speed restrictions on this area of track if the work was not carried out.

The limited access, including no access on the downside (which need to be re-instated), presented a challenge. There was also rock infringing on rail corridor clearances and running water that was ponding in the ballast of the track causing subgrade failures.

The Barnson team was involved in the geotechnical assessment of the rock cutting and soil stability. The site was surveyed by Barnson to determine the current cutting profiles, track location, and current drainage paths. A sub-consultant track designer, Lycopodium, was also engaged to confirm the curved section of track was within curve alignment tolerances.

Barnson’s civil engineers produced drainage calculations and applied the geotechnical cutting parameters. They then provided design drawings for the re-shaping of the cutting, and drainage improvements. Once the works were complete our surveyors re-pegged the track control marks, and re-checked the track horizontal alignment.