TasRail’s network traverses some of the most challenging and varied terrain in Australia, from rugged mountains to coastal plains, dense forests, and river valleys. The rail network navigates steep gradients and winding tracks, adding significant complexities from an engineering perspective.

Restricted site access, narrow track formations, and high embankments often exceeding four metres, demanded a solution that could operate effectively in confined conditions. Remote project locations compounded logistical challenges, with some sites accessible only by hi-rail vehicles. Further, a one-metre-deep layer of loose, unconsolidated ballast rendered traditional borehole and test pit methods ineffective. These operational constraints required an agile, minimally intrusive solution to deliver precise data while ensuring uninterrupted rail operations.

Deploying precision sampling technology

Recognising that conventional borehole and test pit methods were inadequate for the challenges at hand, SMEC conducted an industry-wide search for a minimally intrusive yet precise geotechnical investigation solution. In close collaboration with TasRail, engineers evaluated various alternative methods and ultimately selected Grace Coring’s custom-designed remote intact sample. Mounted on a high-rail excavator, this state-of-the-art technology employs a 100 mm diameter, one-metre-long windowless percussion tube to extract continuous, undisturbed core samples from depths of four to six metres. Operating similarly to an SPT hammer, the system preserves crucial moisture profiles and layer integrity for detailed laboratory analysis, delivering unparalleled insight into the formation and subgrade layers. This precision-driven approach eliminated the need for extensive excavation, ensuring that the investigation proceeded both efficiently and safely within an active rail environment.

Delivering operational excellence with minimal disruption

The innovative sampling method not only secured comprehensive geotechnical data but also achieved significant operational efficiencies. On-site investigation times were reduced by 60%, and the approach was seamlessly integrated with TasRail’s operational schedule, minimising track impact and the need for post-investigation restoration. By preserving the integrity of the active rail network throughout the works, SMEC’s solution delivered both safety and operational excellence, transforming a challenging environment into a model of efficient, minimally invasive engineering.

A collaborative triumph driving industry innovation

The TasRail Formation Renewals Project is the first of its kind initiative in Tasmania to utilise this method. Grace Coring’s remote intact sampler is an innovative approach to geotechnical work that enhances efficiency while minimising disruptions to operations. It can be applied to future rail projects across Australia.