Rail Projects Victoria is currently delivering the $11B Metro Tunnel project to ease congestion in Melbourne’s City Loop, by taking the busiest train lines through a new tunnel under the city. This means more trains, more often across Victoria, with a less-crowded and more-reliable train network.

The construction of the tunnels and five new stations is due to be completed by 2025. The Rail Network Alliance (RNA) will deliver key works to allow the project to commence and meet the required timeline. The transport network in Melbourne will be affected by the construction of this project; therefore, meeting the deadline is crucial to its success.

AECOM is providing detailed design services as the lead designer in an alliance comprising CPB Contractors, John Holland, Rail Projects Victoria and Metro Trains Melbourne. The alliance will deliver works at the eastern and western tunnel entrances, including cut-and-cover tunnelling, decline structures, local reconfiguration and realignment of existing train lines, and the upgrade of public spaces in the vicinity of the portals.

RNA will also deliver rail upgrades along the rail corridor of the new Sunshine to Dandenong Line that will maximise the benefits of the Metro Tunnel. This includes a new platform at West Footscray with a turnback facility, new hot standby tracks and drivers’ facilities and additional resilience crossovers.

RNA was also awarded a major variation to deliver stabling yard upgrades across three stabling sites, platform modifications along the Sunbury Line and the power upgrade required for the existing line.  This includes 27km of overhead line equipment (OHLE) upgrades and two new substations, conventional signalling system upgrades and coordination of the corridor wide interface with V/Line and ARTC.

The majority of RNA works are expected to be finished in line with the completion of the tunnels and stations, ready for opening by the end of in 2025.

Approach

AECOM is providing a design that meets the timeframe, integration, connectivity and maintenance requirements of this project. Some of the key features include:

• Bespoke designs for the cut-and-cover tunnels to reduce the risks and responses required to the different constraints at each portal. At the western portal, this included a diaphragm wall solution with innovative mass concrete props below the base slab to help minimise ground movements.
• An enhanced urban-design outcome at both the western and eastern portals, with designs that incorporate improved shared use paths, greater connectivity and increased and regenerated open spaces.
• Delivering the design through the development of a cloud-hosted federated 3D model that provides a 360° visualisation tool for capturing current conditions, aerial and site photography and other essential information inputs.
• Design solutions that were developed ‘from first principles’ to ensure cost effective and practical design solutions were delivered to suit the brownfield environment the works were delivered in.

Outcomes and value

As a result of the project being spread 50km across Melbourne, from Caulfield in the South-East to Sunbury in the North-West there are multiple work fronts being progressed concurrently. In addition, occupations were staggered across the different rail lines impacted by the works meaning multiple occupations were delivered throughout the year to deliver the works.  This required a significant volume of design packages to be consistently delivered in a timely manner to ensure construction works could be progressed and Work Readiness requirements achieved for the regular occupations that were planned.

AECOM is currently delivering detailed design for this project, ensuring that the project is delivered on time and to the project objectives. This has required mobilising a team to meet the resourcing needs of this $1.8B project with a team of over 200 designers delivering these works.

Sustainability Outcomes

RNA introduced a strategic and innovative approach to delivering sustainable outcomes, focusing on integrating sustainability into plans, designs and delivery of major infrastructure. By collaborating and building ownership across project disciplines/stakeholders, this approach has enabled significant savings in greenhouse gas emissions including:

• Portland cement reduction – with a target to reduce Portland cement content in concrete by 36%, most concrete now poured is tracking above 43% which is equivalent to 25,129 tCO2-e embodied emissions saved
• Embodied emission reductions – the Alliance saved 988 tCO2-e of embodied emissions through smart design and sustainable materials in the Gap Road level crossing removal bridge
• GreenPower – the Alliance has purchased 100% GreenPower electricity for its three main site offices, meaning all electricity consumed is from renewable energy
• Biodiesel generators – the Alliance uses biodiesel generators with B20 biodiesel fuel to power lighting/ventilation units for tunnel works

Initiatives that contributed to the ‘Leading’ ISC rating included:

• Integrating strong management systems and procurement practices like empowering and enabling the leadership and design teams to incorporate sustainability into decision making
• Actively engaging with the community on urban design, active transport and enhancing cultural, historical and social heritage in the local area
• Embedding climate change resilience through early consideration of key risks 
• Delivering water savings of more than 27% by optimising dust suppression, reusing water for construction activities and installing rainwater tanks and sediment ponds
• Contributing to a net ecological gain by creating over three hectares of critically endangered native grasslands and habitat connectivity without relying on biodiversity offsetting schemes
• Incorporating smart design principles that led to ~18% reduction in materials 
• Prioritising community health and wellbeing through active transport corrections and bicycle facilities
• Integrating crime prevention measures through environmental and urban design.