Beyond the tunnel: why a systems approach is critical to metro delivery

As urban railway projects grow in complexity and purpose, old assumptions about construction costs and associated risks are becoming obsolete. Mike Taylor, our global head of rail systems and systems engineering, explains why the industry needs a systems approach to adapt.

Building a subway or metro system is no easy feat. It can involve huge distances tunneling beneath intricate infrastructure — often below some of the world’s most expensive real estate. High costs of tunneling and risks of cost over-runs abound.

Yet, surprisingly, it’s often not the most complex or riskiest aspect of metro projects. Instead, systems and their integration have increasingly become some of the most complicated aspects of delivering urban railways.

Delivering a metro is always greater than the sum of its parts. It requires massive coordination across construction, rail systems (signalling, communications), station systems, operations and maintenance systems, all adhering to safety, sustainability, building, and environmental standards.

Moreover, the local community and local authorities demand seamless integration and community advantages spanning multiple decades.  In summary, it’s the effective intersection of all the systems and elements that determine a true project’s cost and timeline.

As the complexity and cost of metros and, indeed, nearly all rail megaprojects continue to increase, a systems approach has become more critical than ever. By considering a whole rail project and its many relationships — rather than just its component parts — systems thinking enables more cost-effective, timely and sustainable delivery. But what does it take to implement?

Starting with relationships

Successful infrastructure projects depend on successful relationships. With dozens of contractors (and even more subcontractors) operating on behalf of the infrastructure owner and operator, it’s essential for these many parties to create a culture of collaboration.

But while effective collaboration arises from a project’s culture, it’s also a consequence of something far more fundamental: contract structures.  Traditional contract models, based on tried and trusted norms for building generic infrastructure, slice and dice scope into manageable construction chunks.  Fixed price Design and Build contracts and their variants can work quite well for most infrastructure, but these contracts tend to create siloed thinking around just the part of the whole being delivered.

To deliver an entire railway, however, a much stronger culture of collaboration and delivering “the whole” is needed.  The intelligent consolidation of contracts among partners is essential to strong collaboration, while keeping contact and communication streamlined for a safe, effective delivery.  And yet, it’s still common to see contracting arrangements that silo responsibilities, incorrectly apportion risk, and overlook the systems nature of a rail project.

Such a siloed approach has become unworkable: contracting structures — and the collaboration they foster — have never been more important.

On Melbourne’s Metro Tunnel Project (MTP), for instance, AECOM’s teams are helping accomplish two objectives at once: delivering a brand-new metro rail tunnel through the city centre while integrating that tunnel into brownfield metropolitan rail routes. While the Metro Tunnel will be state of the art, the railways that feed into it date back to the 19th century.

Despite the MTP’s integration demands, its delivery is proving successful — so successful that it’s a year ahead of schedule. A key enabler for success has been the systems-focused, alliancing contract model, used by our teams with our project partners and client — facilitating integration of the MTP’s many components for rapid delivery.

An alliancing model isn’t the only way to support strong contract structures. Other Progressive Delivery Models, including an Integration Delivery Partner approach and Progressive Design-Build can prove just as effective — chiefly because they embed systems perspectives and cross-team collaboration into the heart of the project.

Digital integration

While the nature and scale of new transit projects have necessitated a systems approach to contracting structures and collaborative mechanisms, technology has only accelerated this trend.

The introduction of automated transit services and digital signaling systems such as communications-based train control (CBTC) has increasingly digitized transit — even as considerable portions of existing signaling and communications infrastructure remain ‘analog.’

This poses a fundamental systems integration problem. While most metros run CBTC and are segregated from the rest of the rail network, it is not always the case, for example London’s Crossrail and Metro Tunnel Melbourne. As transit operators mesh state-of-the-art CBTC with the century-old, fixed block signaling, what once required purely steel and concrete infrastructure now involves software-centric products to be safely integrated and deployed in a robust environment where they must cope with the huge demands of on-time performance, at all times.

During the delivery phase of a railway, measuring progress on software integration can pose challenges — and generate considerable cost risks — as projects are frequently surprised to find themselves spending far longer on systems integration than they thought they’d need to.

As complex inter-operable rail systems undergo technological advances, user experience demands have also increased.

Today, riders expect ever-greater access to transit data for smartphone applications to navigate rail networks and plan trips.  Riders also want to know where to stand on the platform to get an uncrowded carriage. As a result, data management of live feeds during operation as well as software integration during project delivery have now fallen within the domain of transit delivery.

Looking ahead, as project stakeholders embrace new technologies such as AI, we must remember that new technologies and the systems integration challenges they bring mustn’t remain siloed.

Outcome Oriented Systems Thinking

Perhaps the most dramatic — and long overdue — shift in transit delivery relates to environmental, sustainability and social benefits, where systems approaches can prove critical.

With U.S. infrastructure funding like the Infrastructure Investment and Jobs Act and the Inflation Reduction Act increasingly tied to sustainability, resiliency and social value outcomes, transit projects must deliver far more than just transportation. Community and environmental benefits now directly determine a project’s selection — changing the nature of project delivery.

Transit, by its nature, provides community and societal benefits by providing access through enhanced mobility. As such a new array of equity objectives, such the Justice 40 Initiative in the U.S., now factor social outcomes into project selection. The participation of minority- and women-owned enterprises, local employment opportunities, workforce development and social infrastructure today stand alongside technical innovation when weighing project excellence. As a result, whole communities now fall within a project’s scope, presenting project teams with even broader systems thinking aspects to manage.

Another example of systems thinking is Environmental, Social and Governance (ESG). For decades, designers and builders have focused on minimizing construction impacts on the local environment. But today, they must also minimize climate impacts by reducing emissions and carbon footprint via innovations in low-carbon materials and deliver net biodiversity gains. This has required teams to investigate supply chains and lifecycle impacts, vastly extending a project’s system.

To understand what such ESG outcomes look like in action, we can again turn to Metro Tunnel Melbourne.

In partnership with the client and alliance partners, we helped reduce carbon across the project thanks to several innovations. We cut the emissions from concrete by around 40% through a reduction in Portland cement; saved 988 tCO2-e of embodied emissions through smart design and sustainable materials; and cut water usage by 27% by optimizing dust suppression, reusing water for construction activities, and installing rainwater tanks and sediment ponds.

Social considerations also played a central role in the project. The team actively engaged the community for input on urban design as well as enhancing local cultural, historical and social heritage. The results of this engagement have led to the prioritization of active travel options and f0r public safety measures to be incorporated.

These achievements speak not just to growing interest in driving positive local outcomes on megaprojects — but to the new array of skills needed to simultaneously innovate across both infrastructural, societal and environmental systems.

From part to whole

Today’s urban rail projects have become increasingly holistic: What was once a collection of component parts has become a complex physical, social and environmental system. Delivery teams therefore must solve more technical integration challenges, incorporate digital advances, and deliver a wide array of equity and sustainability benefits.

As we meet this challenge with our clients and partners, our approach is to integrate a systems thinking, outcome oriented mindset from the outset with the aim of delivering positive impacts from day one. With a focus on foresight, agility and predictability, our teams have the scale and expertise to deliver on each key systems integration challenge — from collaboration and digital transformation to sustainability and social value.

Through our partnerships with clients, we’ve witnessed — and shaped — the rise of this new era in infrastructure delivery. It’s one in which a tunnel is no longer the paramount focus of a subway or metro project. Instead, it’s people, partners, and the planet, that must take equal priority.