Untangling a heritage rail loop

As urbanisation increases, cities around the world are becoming congested and overcrowded. Globally, more people live in urban than in rural areas and, by 2050, the United Nations predicts that 66 per cent of the world’s population will live in cities. So how are we planning to accomodate the movement of so many people in our cities?

The Melbourne Underground Rail Loop was constructed in the 1970s to address major congestion at Flinders Street Station (the CBD’s largest and busiest passenger station) and it is now Melbourne’s busiest rail corridor.

The Loop itself connects Melbourne’s largest stations above and below ground for over four million residents of the metropolis. Due to population growth and associated commuter train scheduling demand, the heritage City Loop has reached capacity and became Melbourne’s biggest rail bottleneck.

To ease movement across the CBD, the new Metro Tunnel is being designed to free up the current City Loop bottleneck by complementing the existing loop, and delivering five new rail stations servicing more trains in and out of the city.

Looping back

For Aurecon, working on the Metro Tunnel is history repeating itself, in a good way. For a period of 15 years, beginning in the early 1970s, Aurecon was part of the principal consultant on the original Melbourne Underground Rail Loop.

During the peak design periods, up to 150 design and construction staff were working on this multidisciplinary project, providing technical advice to the Melbourne Underground Rail Loop Authority. Aurecon, as part of the Principal Consultancy, was engaged to manage and develop the design and documentation for the project, and perform the role of onsite engineer during construction.

This project was actually the genesis of the infrastructure arm of Aurecon’s global business.

It’s a proud moment for Aurecon to be able to again contribute to this vital network of transport infrastructure that is at the heart of one of the world’s most liveable cities.

The innovative and bold rail loop pushed the boundaries in underground tunnelling in the 70s, and now Aurecon is back to push the boundaries again with Metro Tunnel.

Getting started

Construction began on Metro Tunnel in late 2016. The project scope covers:

Cutting through the knots

Planning the Metro Tunnel is by no means straightforward for the Aurecon, Jacobs and Mott MacDonald (AJM) Joint Venture. The Joint Venture is the Metro Tunnel technical, planning and engagement advisor for Rail Projects Victoria. During the reference design and procurement phase of the project, they were acutely aware of how complicated such a large-scale rail infrastructure project would be to design and plan for.

Building on significant planning work completed in the lead up to this city-defining, once-in-a-generation project, the AJM Joint Venture focused on untangling complex environmental challenges.

The challenges

To address the incredible scope of the project, the AJM Joint Venture implemented three innovative digital engineering tools to drive greater collaboration and quality outputs from the team:

1. GeoDocs to manage project documentation
2. Metro Maps for geospatial information and access to documents
3. Federated 3D model for clash detection and digital coordination

1. GeoDocs controlling complex information and documentation

The Aurecon, custom-built, GeoDocs platform was selected for the project by the AJM Joint Venture to help manage the significant number of documents required for such a large scale infrastructure project.

GeoDocs is an internet-based collaboration platform that enables project documentation to move seamlessly and efficiently through the four stages of the information management life cycle. This was critical for the complexity and scale of Metro Tunnel.

“The power of the system is that it can be tailored to suit large infrastructure projects, which typically generate a substantial number of documents to create, iterate, verify and deliver,” said Richard Syme, Aurecon Digital Specialist.

“For Metro Tunnel, there were thousands of documents housed in GeoDocs, all of which were being shared between more than 350 people at the peak of activity. A traditional document management system would never have handled this volume of documents in such a collaborative way. GeoDocs allowed us to scale the document management system without losing any of the integrity or performance attributes of the system itself,” said Syme.

2. Metro Maps delivering good vibrations for buildings above

Planning to build the Metro Tunnel in a dense urban environment meant considering vibrations, noise and other interferences underneath buildings, equipment and people – referred to as sensitive receivers.

Sensitive receivers were defined as residential dwellings, commercial premises, culturally significant and heritage-listed buildings, and electromagnetic-sensitive medical equipment.

Metro Maps was the AJM Joint Venture’s Geographic Information System (GIS) used to map over 800 buildings along the Metro Tunnel alignment. The Metro Maps Building Register provided access to more than 10 000 documents relating to sensitive receivers along the planned route.

By combining Metro Maps with GeoDocs, engineering teams could record and share the details/requirements for each sensitive receiver, and use the information to plan construction mitigations.

For example, the electromagnetic-sensitive receivers mapped in Melbourne’s Parkville Health and Research Precinct highlighted to stakeholders the scope and proximity to proposed railway infrastructure.

Arming the team with building information

The documents housed in the Metro Maps Building Register included architectural drawings, historical plans, photographs, design drawings and as-built drawings. Nearly 10 000 documents for the 800 buildings were housed in GeoDocs, and available to be accessed by the design teams and client.

Armed with this building information, the design teams rendered 3D models of key buildings and their foundations. These fed into the project’s federated 3D model which assisted with disciplined design coordination, clash detection and communicating design changes with the client and stakeholders.

Each building was assigned a unique identifier, which when clicked on in GIS, would reveal all known information about that building and retrieve documents from its file store in GeoDocs.

3. 3D modelling for clash detection and coordination

Doing what couldn’t be done in 2D

“The use of this digital engineering solution created a coordinated and consistent approach that couldn’t be realised in a 2D environment. It maximised data sharing and promoted collaborative working,” said Richard Syme.

The federated models and reports were vital for design coordination workshops. Clashes that were detected allowed designs to be amended before construction commenced, and/or provisions to be made for the relocation of utilities during the construction period.

The federated model was also used in the project’s reference design to inform construction contractors in relation to work packages.

The AJM Joint Venture’s use of digital infrastructure enterprise tools, GeoDocs, Metro Maps and the Federated 3D model, is delivering value across all critical project stages and giving stakeholders the power to manage, plan, share and drive quality.

Easing congestion

Turn-up-and-go for Melbourne

The three digital pillars created at the beginning of the Metro Tunnel project will deliver quality, value and improved commercial outcomes throughout the detailed design and construction stages.

The Metro Tunnel is the first step towards turn-up-and-go train services in Melbourne, similar to some of the world’s largest cities. Such service frequency is exemplified in cities like London, New York, Hong Kong and Singapore.

When completed, Metro Tunnel will increase the capacity, reliability and efficiency on the network by catering for 39 000 more passengers during each peak period, and transforming Melbourne’s rail network by unlocking critically needed capacity.

The project will reshape travel demand, allowing for future extensions to the tram and rail network as Melbourne grows towards a projected population of 7.5 million in 2025. Three of the five new underground stations along the Metro Tunnel corridor will bring heavy rail to areas not yet connected to the rail network.

"We’re building the turn-up-and-go train network Melbourne needs – where trains come so often you can throw away the timetable." Premier of Victoria, The Hon. Daniel Andrews MP

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