Redefining sustainable infrastructure
On 28 March 2024, the newly constructed Narre Warren Station officially opened on Melbourne’s Pakenham Line, removing a notorious and congested rail-road crossing and delivering a safer, modern public transport hub. Beyond the construction achievement, the project marks a milestone in material efficiency and sustainable design through the innovative use of stainless steel.
A materials breakthrough
The original ceiling design called for 30 tonnes of 800mm carbon steel deep beams – considerable welded elements that would have been heavy and disruptive to install. The beams were intended to support the ceiling spanning between the tracks above the concourse. Instead, Built Environs turned to ASSDA Member Ronstan Tensile Architecture to investigate whether a lighter, more efficient solution was possible.
The result was a structural first for metro infrastructure – a pair of stainless steel cable bow string trusses in each of three bays, spanning 25 metres between bridge crossheads to support the ceiling system. With just 3 tonnes of precision-engineered Ronstan ACS2 8mm and 14mm diameter stainless steel cables, fittings, and bespoke galvanised elements, the design replaced the need for 30 tonnes of conventional structural steel.
Why stainless steel?
Central to the solution was grade 316 stainless steel, used for the bright drawn strand wire rope cables and machined fittings. The material was chosen for its high strength-to-weight ratio, longevity, corrosion resistance, and minimal maintenance requirements, critical attributes for a fully enclosed structure that is nearly impossible to access within a busy rail environment.
By reducing steel usage by 90%, the project dramatically lowered resource dependency and cut the carbon footprint associated with steel production, transport, and installation.
Stainless steel’s durability ensures the cable system will deliver decades of performance without costly or disruptive maintenance, further extending its sustainability benefits.
Efficiency through design
The lightweight nature of the stainless steel cable system delivered significant construction efficiencies. Unlike the original beam design, the modular truss system could be installed incrementally, without shutting down rail services. Its low self-weight also reduced handling complexity and avoided the need for oversized lifting equipment.
Ronstan’s philosophy of “applying the science up-front” played a principal role. The company invested heavily in design development, including load analysis, cable geometry modelling, proof and destructive testing, and a rigorous QA/QC process under ISO 9001 certification. This front-loaded engineering approach ensured that the on-site works were efficient, safe, and risk-minimised.
A sustainable model for the future
The Narre Warren project underscores a broader industry shift towards lightweight, resource-efficient structural systems. Cable-supported designs not only use fewer raw materials but also offer flexibility for future modification or deconstruction, aligning with circular economy principles.
As the first of its kind in this application, the stainless steel cable truss system has set a precedent for future stations in Melbourne and beyond. It demonstrates how intelligent material substitution – replacing conventional carbon steel with stainless steel – can achieve structural efficiency, lower embodied carbon, and extend asset life.
Ronstan and the project’s success was recognised with the 2024 ASSDA Fabricator Project of the Year Award in the Architecture, Building, and Construction category. The station stands as proof that when design excellence meets stainless steel, the result is infrastructure built for generations.
Photos courtesy of Ronstan Tensile Architecture.
The article was featured in Australian Stainless Magazine 83.
