Melbourne Metro Tunnel Project—Phase 1: Early Works

Tabled: 6 June 2019

3 Detailed design and environmental approvals

Major transport projects have the potential for wide-scale impacts on the community and the natural environment. They should be carefully planned and well designed, should undergo scrutiny of proposed construction techniques and designs, and should be diligently assessed for environmental impacts before construction starts.

This part of the report assesses whether the reference design for the Melbourne Metro Tunnel Project:

  • was informed by reliable modelling and supported by realistic and validated data on demography, land use and travel patterns
  • demonstrates a flexible future-proofed solution.

It also examines whether the EES and statutory planning processes:

  • adequately considered environmental risks and site-specific issues
  • recommended effective mitigations and controls.

3.1 Conclusion

The reference design developed by RPV and its advisers used a range of modelling and simulation tools, but the uncertainty of the outputs from the strategic model means that the data used to develop the station-level models is also uncertain. Potential underlying demand forecast errors from the strategic model about patronage growth could mean that the new stations reach full capacity sooner than the business case expects.

RPV has not explicitly assessed a scenario where the scale and timing of passenger demand exceeds the passenger forecasts and future scenarios described in the business case. Although RPV took a 'conservative' approach during the design process, there is a risk that the new stations may not have enough entrance and exit capacity to meet future demand or enough elevators or escalators in the stations, if the underlying forecasts are unreliable.

There are practical construction and engineering limitations on how many entries and exits can be built for deep stations in the CBD. However, the reference designs—and the detailed tendered designs from the PPP consortium for the stations, which are now under construction—have limited provisions to increase the number of street entries at some of the stations in the future.

Building the five new underground stations with platforms long enough to allow for 10-car HCMTs—compared to the seven-car HCMTs that will use the tunnels on 'Day 1'—is an effective future-proofing element of the design to meet unexpected demand increases. However, DoT and RPV have inadequately defined patronage trigger points to bring forward unfunded projects—such as the early introduction of 10-car HCMTs or the extension of 35 station platforms needed on the Sunbury/Melton and Pakenham/Cranbourne corridors to allow the longer trains to run on the network.

The EES and statutory planning processes for the Melbourne Metro Tunnel Project were comprehensive. They effectively considered stakeholder perspectives, key environmental risks and planning issues relevant to the project.

The EES process informed the development of a comprehensive suite of EPRs and other mitigations and controls that are appropriate for the identified project risks.

The statutory planning process has been effective in recommending strategic environmental management strategies and performance outcomes. However, statutory planning does not have a role in recommending detailed responses to environmental risks. DELWP relies on RPV and the Independent Environmental Auditor to make sure these measures will be in place but has limited visibility of this assurance work.

3.2 Developing a concept design and assessing impact on the environment

Concept design process and its purpose

The state invested significant funds to develop a detailed concept design for the Melbourne Metro Tunnel Project, for which the three main purposes were to:

  • demonstrate a technically feasible reference design prior to engaging with the market
  • allow the EES process to commence before final designs had been developed
  • undertake the procurement processes for the PPP at the same time as the EES to allow the winning consortia to be aware of any environmental risks and controls.

Environmental assessment and planning approvals

The EES process used the outputs from the detailed design work to understand the impact of the proposed project on the environment, and to identify any risks that required mitigation or control.

These processes involved an in-depth examination by an independent expert panel, public submissions and hearings, and an assessment by the Minister for Planning.

As a result, RPV and DELWP developed a suite of monitoring requirements, as well as statutory planning mechanisms and approvals.

3.3 Modelling inputs for the detailed design

Modelling of passenger demand at the station level

Modelling for the Melbourne Metro Tunnel Project produced long-run forecasts to 2046. For design purposes, the reference year for station capacity was set at 2056, or 30 years after the tunnels' planned opening. RPV and PTV applied a straight line 25 per cent uplift to the 2046 VITM forecasts to produce a notional design scenario for 2056.

DoT advised us that the rationale for the straight line 25 per cent uplift was that it:

  • extrapolated the VITM-generated growth trend in train boardings from 2031 to 2046 (2.2 per cent compounding per annum, or 24 per cent over 10 years)
  • extrapolated the forecast growth in jobs from 2031 to 2046 in the City of Melbourne (2 per cent per year, which is 22 per cent over 10 years).

The base data for the other two finer grain station-level models (ClicSim and STEPS) was also a VITM output. This means that any uncertainty or error arising from the VITM forecasts cascades down to the other station-level models.


ClicSim is a simulation tool used to model the movement of trains through the metropolitan rail network. ClicSim models the location of trains and passengers on a second-by-second basis for the entire Melbourne metropolitan rail network.

A private company developed ClicSim for DEDJTR (now DoT) in 2007 to assess the capacity of the City Loop and inner core stations. The simulation can inform understanding of how the rail system will cope with future demand. The future demand figures input into ClicSim were derived from VITM.

The station-level models refined the VITM outputs to give a more accurate picture than VITM can provide of how demand will be distributed across the network.


STEPS is a detailed simulation tool used for modelling the movement of passengers through a train station. The simulation can be used to identify the areas of a station that may become crowded due to passenger movements.

It can also be used to test proposed design solutions for areas showing overcrowding.

Figure 3A shows how a range of assumptions indicating an area of uncertainty interact through the various models at different stages of demand forecasting.

Figure 3A
Sources of modelling uncertainty

Figure 3A shows how a range of assumptions indicating an area of uncertainty interact through the various models at different stages of demand forecasting.

Note: GDP = gross domestic product.
Source: Aurecon, Jacobs and Mott McDonald Joint Venture, Stage B Demand Modelling report, October 2016.

3.4 Detailed design of the stations

Station design process

RPV used expert advisers to help design fit-for-purpose stations that would meet the 'Day 1' demands of the railway in 2026 (the business case opening date) and also have enough capacity and design flexibility to meet forecast demand out to 2056, including notional additional passenger demand from the running of future Airport Rail, Melton and Rowville lines through the tunnel.

DoT's strategic network development plans designate Parkville Station as a future underground interchange for a potential Melbourne Metro 2 line from Clifton Hill to Newport, so the impact of this future scenario was also modelled to inform the station design process.

The design and modelling work involved a complex and interrelated process of scenario testing for each new station. This iterative process was meant to unify the specific outputs from demand forecasting, station design and operational planning teams.

RPV's advisers ran detailed modelling simulations to identify passenger flows through the metro stations during different situations, such as normal operations, 'degraded' mode (such as when there are a number of train cancellations or other disruptions on the rail network), or during an emergency when passengers need to rapidly exit stations.

This modelling informed the design width of the platforms, since wider platforms can accommodate more passengers, and the number of escalators needed to meet forecast demand.

The design width of the future station platforms was compared to the notional platform width derived from the raw passenger demand modelling. Adjustments were then made within engineering and design limitations to provide optimal space allocation for waiting passengers.

To calculate the number of escalators needed, the forecast patronage was tested against an engineering design rule-of-thumb of 100 people per minute, per escalator. To better understand station design resilience in the face of abnormal operations or demand, the modelling also tested scenarios where an escalator was out of service and where train delays led to increased crowding.

Analysis of the design and model outputs

The patronage data assumptions used for station design purposes, as well as the iterative design process, led to the 2056 forecast demand equalling the maximum designed throughput capacity of the tunnels—or 24 fully loaded 10‑car HCMTs per hour in each tunnel.

The implication of this outcome is that the stations could reach full capacity sooner than the business case expectations if the underlying demand forecast from the models underestimated growth in patronage. Once this limit is reached, no opportunity for substantial expansion or design change is available.

In light of this, we consider that DoT and RPV have not explicitly defined the potential passenger load trigger points to bring forward other currently unfunded projects on the rail network that may be needed if the strategic patronage forecasts have underestimated demand.

In particular, DoT has not explicitly defined the time frames required to extend platforms at more than 35 stations to allow for an earlier rollout of 10-car HCMTs across the Sunbury/Melton and Pakenham/Cranbourne corridors. This decision would require commercial negotiations with the PPP building the HCMTs and adequate time frames for the extra carriages to be constructed and commissioned in time to meet passenger demand.

Future-proofing of station designs

DoT developed reference designs for the new stations to achieve the modelled passenger demand and operating profile for the rail tunnels. Due to the presence of pre-existing adjoining structures, as well as heritage considerations, there are pragmatic limits to the number of entry and exit points that can be realistically provided.

RPV considered several future-proofing options for the stations in the reference design and these options have also been included in the designs tendered by the PPP consortium:

  • North Melbourne—the 'Day 1' station entry is sized to meet planned patronage. An additional western entrance is future-proofed into the design and could be provided as part of a development in the precinct by property developers once the precinct starts to be built out.
  • Parkville—the street entrances and concourse have been designed to accommodate future patronage for a four-platform station (incorporating a future Melbourne Metro 2 connection). In addition, the platform has been 'space-proofed' to allow for future interchange escalators between the Metro Tunnel and future Melbourne Metro 2 platforms. Also, an option for a Barry Street entrance is future-proofed on the south side of Grattan Street.
  • State Library—RPV advises that conservative assumptions (the maximum possible number of people using the escalators per minute) have been made about the number of passengers using the State Library and Melbourne Central stations, by basing the patronage through the new entry portal and escalators that will be built at the north-west corner of La Trobe and Swanston streets on the six platforms that will be able to access the entry.
  • Town Hall—the tendered design allows for a potential future 'pop-up' entry near the Town Hall on Collins Street, extending from the new station box. A 'knock-out' panel has been allowed for at the northern end of the station (on the west side of Swanston Street) that could incorporate a possible future basement entry to the station from the western vicinity of Collins Street. These potential entrances are not in the current scope of the project and would need additional funding and construction.
  • Anzac—this station has no future-proofing options due to its constrained footprint in a busy road junction. However, a need for a southern street entry was identified during concept design and has been incorporated into the tendered design. This design outcome allows for a pedestrian underpass through to the northern side of St Kilda Road, as well as a direct connection to trams.

The Anzac Station design features entrances on either side of St Kilda Road, an underground pedestrian walkway and direct passenger access to trams. Image courtesy of RPV (Metro Tunnel website).

The Anzac Station design features entrances on either side of St Kilda Road, an underground pedestrian walkway and direct passenger access to trams. Image courtesy of RPV (Metro Tunnel website).

Vertical transport in the new stations

Apart from these examples of future-proofing in the reference designs and the designs that the PPP consortium tendered to the state, the stations do not include additional shell space or shafts for escalators and elevators if needed in the future.

The station-level modelling focused on the use of escalators as well as expected elevator usage, based on analysis of existing patterns of elevator usage observed at Melbourne Central station. We did not, however, see evidence that the designed provision of vertical transport has explicitly considered emerging future demographic profiles of public transport users, such as frail but active elderly passengers using walking aids and mobility buggies, and more parents with young children in pushers/prams.

Without design flexibility or reserved space, the installation of future vertical transport, particularly elevators, will be extremely costly and unlikely to proceed, even if it is clearly required. The implication for passengers with mobility challenges is that long queues could form at elevators due to their relatively small size and number, and an inability of the station design to meet future growth in demand from this type of passenger.

Notwithstanding our findings about station design and crowding implications, RPV advised that it included a key mitigation for station overcrowding in the reference design parameters. Each station has a safety requirement to have capacity for a worst-case fire evacuation scenario of two crush-loaded 10-car HCMTs arriving at the same time on a crowded island platform. RPV advised us that this safety requirement was included in the PPP consortium's tendered designs.

A crush-loaded 10-car HCMT would carry about 2 000 people. In an emergency, two fully loaded trains, plus a busy platform full of passengers waiting for trains in both directions, would require the swift evacuation of 6 000 to 8 000 passengers using all available vertical transport in the station.

In emergency situations, it is likely that the stations would be closed at their surface entries and all escalators would need to operate to focus on evacuating passengers to the surface. This procedure would add one or more escalators to the number typically available at peak times.

3.5 Environmental assessment and planning approval

Environment Effects Statement and environmental strategies

In September 2015, the Minister for Planning declared that the Melbourne Metro Tunnel Project needed to undergo an EES process to assess its environmental effects.

RPV, in consultation with DELWP, developed the EES documentation that identifies the project's potential environmental effects and any necessary mitigation measures, including a draft EMF and EPRs. The Minister for Planning released the EES for public review between 25 May and 6 July 2016, and it attracted 379 submissions.

Figure 3B shows the EES process and post-EES approvals of environmental strategies for the Melbourne Metro Tunnel Project.

Figure 3B
EES process and post-EES approval of environmental strategies for the Melbourne Metro Tunnel Project

Figure 3B shows the EES process and post-EES approvals of environmental strategies for the Melbourne Metro Tunnel Project.

Source: VAGO, based on DELWP information.

DELWP established a joint IAC to consider the EES, public submissions and draft planning controls for the project. The IAC conducted public hearings over 33 days. In November 2016, the IAC provided a report to the Minister for Planning.

The report concludes that the project can achieve acceptable environmental outcomes and impacts can be adequately managed. It also recommended changes to the EPRs. One example of an impact mitigation measure that arose from public consultation and the IAC hearing process was that RPV develop and implement NEPs. Figure 3C discusses this in detail.

Figure 3C

A key issue identified throughout the EES process was the impact of the Melbourne Metro Tunnel Project on traffic and transport during and after construction.

NEPs were one of the proposed ways to manage construction impacts on roads. One EPR requires contractors to have a transport management plan that includes the implementation of NEPs in areas near the Parkville and Anzac precincts.

NEPs are road network upgrades that help traffic flow during road closures and lane reductions. NEPs, such as those involving closed-circuit television and Bluetooth receivers, can provide up-to-date information on traffic conditions to monitor travel behaviour and identify road incidents.

DoT and RPV did not initially include NEPs as part of the EWMC scope because RPV procured the EWMC before the EES process concluded. In response to the final EPRs, RPV directed the EWMC to undertake NEPs specified in the EPRs. RPV also expanded the scope of NEPs to other early works construction precincts.

Part 4 of this report discusses NEPs in detail.

Source: VAGO, based on DELWP and RPV information.

In December 2016, the Minister for Planning released the Minister's Assessment, which concluded the EES process for the Melbourne Metro Tunnel Project. The Minister's Assessment found that the environmental effects of the project were acceptable, subject to recommended actions such as changes to selected EPRs, the EMF and the Urban Design Strategy.

Minister's Assessment

The Ministerial guidelines for assessment of environmental effects under the Environment Effects Act 1978 state that the Minister's Assessment will consider, among other things, the EES, IAC report and public submissions.

DELWP's advice to the Minister for Planning on the Minister's Assessment was forthright and covered the key material related to the project's potential environmental risks. DELWP drafted the Minister's Assessment, considering the EES and covering key matters raised by the IAC report and public submissions.

The Minister's Assessment addresses 16 environmental effect areas. DELWP discussed the IAC report and/or public submissions in the Minister's Assessment for 10 of the 16 environmental effect areas.

For these 10 areas, the Minister's Assessment accurately reflects the perspectives of the IAC report and submitters. Our analysis showed that the Minister's Assessment either gives a summary or includes direct quotes from the IAC report, which also included public submissions.

For the remaining six environmental effect areas, there is little documentation showing how DELWP considered the IAC report and public submissions. The Minister's Assessment did not reference—and DELWP did not separately document—its consideration of both information sources.

DELWP advises that it took a risk-based approach when drafting the Minister's Assessment and do not consider that there is a requirement to acquit every IAC mention and public submission. This approach allowed DELWP to dedicate more extensive discussions to the issues that DELWP assessed as having a greater environmental risk or impact, such as noise, vibration, transport and traffic.

DELWP faced considerable time pressure to publish the Minister's Assessment to meet the time frames set out in DELWP's internal Quality Management System. According to the Quality Management System, the Minister for Planning must release the Minister's Assessment within 25 business days of receiving the IAC report. To meet this requirement—and to allow enough time for DELWP internal reviews and consideration by the Minister for Planning—DELWP had to complete a first draft of the Minister's Assessment about 10 working days after receiving the IAC report.

While a risk-based approach is pragmatic when there are time constraints, DELWP does not have clear risk-assessment criteria to guide which IAC or stakeholder issues the Minister's Assessment should address. DELWP advised that this decision is usually based on the technical knowledge and expertise of the staff drafting the Minister's Assessment.

Despite the lack of documentation for these six environmental effect areas, DELWP's assessment that these areas are low-risk is consistent with the IAC report's conclusion. An example is the issue of surface water, which DELWP assessed as low risk and therefore not warranting further discussion in the Minister's Assessment. This assessment is consistent with the IAC report, which assessed surface water-related risks as low to very low.

Another environmental risk that DELWP did not discuss in detail in the Minister's Assessment, but which was mentioned in the IAC report, was the issue of electromagnetic interference (EMI). Figure 3D discusses this in detail.

Figure 3D
EMI identified through the public submission process

EMI can occur when an electronic device's electromagnetic field disrupts the operation of another device. RPV did not identify EMI impacts when DELWP determined the EES scope.

EMI became one of the key issues considered by the IAC after it received submissions and evidence from The University of Melbourne. It was concerned about the potential EMI impact on its sensitive facilities and equipment near the Parkville Station precinct.

During the public hearing process, RPV responded to the University of Melbourne's concerns by proposing two new EPRs—EMI1 and EMI2—that aim to ensure that RPV and contractors understand and manage EMI impacts from the Melbourne Metro Tunnel Project.

The IAC acknowledges in its report the potential EMI impact on the operation of sensitive equipment. The IAC was satisfied that the new EPRs are appropriate in identifying and managing EMI impacts.

The Minister's Assessment determined the proposed EMI EPRs, as recommended by the IAC, are appropriate and that they should be adopted.

Source: VAGO, based on DELWP information.

Environmental strategies

After the Minister's Assessment, DELWP recommended—and the Minister for Planning approved—the following suite of frameworks and guidelines to manage and mitigate identified risks and impacts:

  • an EMF, which includes the EPRs, Business Support Guidelines for Construction and Residential Impact Mitigation Guidelines
  • an Urban Design Strategy
  • a Community and Stakeholder Engagement and Management Framework.

DELWP's advice to the Minister for Planning to approve these documents was sound. DELWP assessed whether these documents aligned with the IAC and Minister's Assessment recommendations, EPRs or other relevant sources. For example, when recommending approval of the Urban Design Strategy, DELWP assessed the proposed strategy against the IAC report and Minister's Assessment recommendations, as well as those from an expert panel that the IAC convened during the hearing process.

Statutory planning outputs

An Incorporated Document is the applicable planning tool that regulates the use and development of land for the Melbourne Metro Tunnel Project. This was an outcome of the combined EES and planning process to streamline statutory planning approvals for the project.

Planning Scheme Amendment GC45 inserted an Incorporated Document into the four planning schemes relevant to the Melbourne Metro Tunnel Project—Melbourne, Port Phillip, Stonnington and Maribyrnong. This made the Incorporated Document the planning tool for the project, 'switching off' all other planning provisions in these four planning schemes. Planning Scheme Amendment GC45 also made the Minister for Planning the responsible authority for planning provisions applicable to the project, which means that local government is not involved in approving any planning matters relating to the project.

The Incorporated Document gives statutory weight to the planning and environmental management strategies—specifically the EMF (EPRs) and Urban Design Strategy—because it requires RPV and its contractors to carry out the Melbourne Metro Tunnel Project according to these strategies.

Under the Incorporated Document, the Minister for Planning must approve an Early Works Plan (EWP) for early works to begin. Contractors are responsible for drafting the EWPs and demonstrating how they will conduct early works according to the EPRs and the Urban Design Strategy. The Incorporated Document requires contractors to develop the relevant project land according the EWPs.

The Minister for Planning approved three EWPs relevant for this audit—specifically, the plans relating to the EWMC, Yarra Trams and the PPP consortium.

We looked at the adequacy of DELWP's advice to the Minister for Planning to approve the EWPs and, more broadly, the role of planning to ensure environmental mitigation measures will be in place.

Early Works Plans
Compliance with the Incorporated Document

DELWP has ensured that EWPs comply with the Incorporated Document. Section 4.10 of the Incorporated Document establishes a range of requirements in relation to EWPs, such as the stakeholder consultation process (sections 4.10.4–4.10.6), and that they demonstrate compliance with the EPRs and Urban Design Strategy (section 4.10.3).

When recommending that the Minister for Planning approve the EWPs, DELWP attached a standard assessment template that clearly showed how proposed EWPs comply with relevant sections of the Incorporated Document.

Stakeholder consultation

Section 4.10.6 of the Incorporated Document requires the Minister for Planning to consider all written submissions and responses to issues raised when deciding whether to approve EWPs.

DELWP considered stakeholder perspectives and contractor responses when recommending approval of the EWPs, though it was not consistently clear to us how DELWP assessed them as it has not always documented this assessment.

For all three EWP briefings, DELWP received EWP stakeholder consultation reports and attached them to its briefings to the Minister for Planning. These extensive reports detail the entire EWP consultation process, including all submissions and corresponding contractor responses.

DELWP advised the Minister for Planning that the consultation process was adequate in identifying potential stakeholder issues and contractors had adequately responded to these submissions.

We asked DELWP about the basis of its assessment of the stakeholder consultation report because this was not clear in its briefing. DELWP advised that most contractor responses said that environmental sub-plans would be in place to address concerns noted in a submission. DELWP also advised that most submissions were concerned with the impact rather than the nature of the works and, on that basis, preparation of environmental sub-plans was an appropriate response.

DELWP took a reasonable risk-based approach to assessing compliance with the consultation requirements of the Incorporated Document, focusing its documentation efforts on main works—the next and more intensive construction phase of the project—that will have a greater impact on stakeholders.

DELWP has developed a template so that it can document a more comprehensive assessment of consultation summary reports when reviewing development plans for the Minister for Planning's approval. The PPP consortium received 1 507 submissions relating to its five Station Precinct Development Plans—in comparison, the EWMC's EWP received 77 submissions.

DELWP is taking a methodical and transparent approach for this higher-risk phase of the project.

Statutory planning role in environmental risk mitigation

The Minister for Planning approved the EMF and EPRs. The EMF sets out the governance structure for environmental management for the Melbourne Metro Tunnel Project. According to the EMF, RPV is responsible for environmental oversight, with an Independent Environmental Auditor—appointed by the contractors—responsible for conducting and providing regular audit reports to RPV and the contractors. The EPRs set out the environmental outcomes that RPV and contractors must achieve.

EPRs do not prescribe the mitigation measures necessary to achieve the intended environmental outcomes. Instead, contractors detail their mitigation measures in sub-environmental plans. Under the EMF, RPV—not the Minister for Planning—is responsible for approving these sub-environmental plans. DELWP advised that this is because RPV has the capacity to do so. It would be challenging for the Minister for Planning to assess and review all sub-environmental plans for the life of the project. For early works alone and across three contractors, there are at least 21 sub-plans.

DELWP's primary role is setting the strategic environmental framework and performance outcomes. Although the EWP approval process provides DELWP with some assurance on how contractors will comply with the EPRs, DELWP relies on RPV and the Independent Environmental Auditor to ensure this occurs in practice and to provide assurance to the Minister for Planning that contractors have indeed established and implemented sub-environmental plans as set out in EWPs.

Given that RPV is the project owner, a role conflict might emerge in ensuring timely progress of the project, versus overseeing management of environmental impacts. DELWP acknowledged this potential role conflict, but advised us that:

  • it is common statutory planning practice for project proponents to also be responsible for environmental management
  • RPV is part of the state and must follow all applicable state laws and requirements, and therefore has an enduring interest in appropriately managing and mitigating any environmental impacts from the Melbourne Metro Tunnel Project
  • the governance structure set out in the EMF was subject to EES public consultation and there were no adverse comments.

We also note that the IAC report did not raise any issues regarding RPV's role in environmental management.

Beyond the legal requirements between RPV and its contractors and the governance structure in the EMF, the Minister for Planning and the Environment Protection Authority have enforcement powers for breaches related to the Incorporated Document and specific EPRs, although they would need to know when there is non-compliance in order to take action.

Increasing public transparency around compliance and performance is one way to make sure the Minister for Planning and the wider public understand how well the environmental protections are working.

The West Gate Tunnel Project, which is another large and complex transport infrastructure project under construction, has an EPR in place that requires the Independent Reviewer and Environmental Auditor (equivalent to the Independent Environmental Auditor for the Melbourne Metro Tunnel Project) to publish all its reports in the public domain.

Publishing environmental audit reports can help drive contractors' compliance with EPRs and environmental management plans, as their performance is subject to public scrutiny.

We consider that this requirement should be applied not only to the Melbourne Metro Tunnel Project, but other major public infrastructure projects that are going through the EES process and will have an EPR framework in place.

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