Reconceiving Utilitarian Urban Spaces

From Burying Highways to Tactical Urbanism and the Impactful Stuff In Between

Our urban environments are layered—the result of decades or even centuries of private development, public infrastructure and incidental componentry yielding an often unwieldy, uncoordinated aggregation.1 Among it all is lost space, no-man’s land that has, for one reason or another, been left over, looked over or purposefully neglected. You might not see it at first, but it’s there, often in plain sight, lurking behind buildings, under overpasses or even high above on viaducts.

Disused rail tunnels beneath Wynyard are a legacy of JJC Bradfield’s vision for a Northern Beaches rail line. Used as storage today, they could be reconceived as urban amenity in the heart of the CBD.

Often the spaces are the direct result of infrastructural interventions, the types of spaces that mega projects in the modern city seek to reduce or eliminate through design refinement. But what of the bridge undercrofts, the abandoned overpasses and the rusting relics of industry long since banished to the outskirts of the city? How can these urban spaces, often seen as liabilities, be amenitised, turned into assets for modern urbanites? Many cities around the world are grappling with these questions—among them Melbourne, as it examines what to do with its ‘desolate’ spaces.2

Rails to Trails—A Global Phenomenon

If there is a poster child for urban infrastructure reuse for public amenity, Manhattan’s High Line would be a logical contender. While not the first example of the reuse of unused infrastructure, it is one of the highest profile, most widely known and wildly successful.3 The project transformed a long-disused elevated industrial railway line that sliced through the westside of lower Manhattan into a 2.2-kilometre-long linear park—a project type known as ‘rails to trails’—that attracts millions of visitors annually.

The catalytic nature of such projects is clearly visible in the surrounding area, epitomised by the underway redevelopment of Hudson Yards, leveraging the air rights above a rail yard at the northern end of the High Line. Closer to home, this has inspired the recently unveiled mega project plans to develop 24 hectares above Sydney’s Central Station rail yards and platforms, announced this week by the NSW Government.4

The High Line drew inspiration from an earlier international precedent, the Promenade plantée René-Dumont that opened in Paris in 1993, which, like the High Line, reimagined a disused rail line as a public park. And since the opening of the High Line in the early 2000s, its popularity has been an inspiration for similar projects around the world.5 The trend is not limited to urban areas, either, with disused rail corridors repurposed into long-distance trail connectors in regional and rural areas—something the NSW State Government has thoroughly embraced.6

DesignInc Sydney - Byron Bay Bus Interchange
The new Byron Bay Transport Interchange reclaims the space alongside the former Byron Bay Railway Station (closed 2004). The former rail line serves as a multi-use trail, tying the new interchange into a proposed regional trail network.

Transitions Beyond Trains

Of course, the trend of repurposing or repositioning infrastructure is not limited to rail-based transport. Underutilised car parks or car parks located in prominent urban locations have been a target for reimaging.7 Similarly, major roadways have been either undergrounded or fully removed, providing for new public spaces such as parks and plazas, or even rewilding through efforts to restore waterways and natural amenity long lost under urban development.8 Presently in Australia, there have been proposals to repurpose or remove the Cahill Expressway in Circular Quay to create new public space on Sydney Harbour.9

Even infrastructure to serve water-based and air-based transport options have been transformed. From the 1960s onward, redevelopment of working harbours in inner cities has been a major catalyst for urban redevelopment as port operations moved to remote locations following containerisation. The trend, which emerged in Baltimore, swept the globe, from London to Rio de Janeiro and locally in Sydney, Melbourne and Brisbane.10 Following this trend of departure of heavy infrastructure from urban cores, airports positioned close to population centres are increasingly being turned over to public lands as well.11

The old docks at Newfoundland Quay serve as the backdrop for the mega mixed-use precinct of the London Docklands.

Even more broadly, the potential extends beyond transport-related infrastructure. In Copenhagen and Istanbul, old water cisterns have been transformed into public spaces that can host events and art installations.12 In Sydney, the old Paddington Reservoir was reborn as a partially sunken public park after serving a stint as a service station and garage.13

This is all to demonstrate that the reimagination of infrastructure—or former infrastructure—into public space is varied, prevalent and not restricted by culture, country or potential future use.

From Grand to Guerrilla

As the mega projects mentioned above repositioned infrastructure in the context of human-centric environments, a more democratised application appeared at a scale not beholden to mega investment. Through the emergence of a concept known as ‘tactical urbanism’ in the early 2000s, design of space for the public was adopted by the public, allowing people most impacted by the urban form to express and implement their visions.

The rise of tactical urbanism offered residents of the city the opportunity to instate changes that could positively impact the urban realm through guerrilla installations, such as the emergence of Park(ing) Day—a day now celebrated globally by citizens transforming car parks into parklets.14 While the tactical urbanism movement and the implementation of its principles started in the streets, it was soon sanctioned by governments.

Janette Sadik-Khan, as commissioner of the New York City Department of Transportation, met great success with the technique. By leveraging inexpensive and easily reversible interventions such as paint and planter boxes as proof-of-concept for otherwise controversial projects—such as removing vehicle travel lanes through Times Square—she illustrated positive outcomes of public space generation to elicit community and, ultimately, government buy-in to enact permanent change.15 We see this legacy today in ‘pop-up’ bike lanes and outdoor dining zones that have become de rigour in the post-Covid city.

Creating Lasting Impact

Between the extremes of mega transformations (such as the High Line) and temporary guerrilla installations (such as Park(ing) Day), sits the majority of opportunity for creating lasting impact in our cities. Returning to the situation that Melbourne finds itself in—a question of what to do with spaces under bridges in the city—we can look at the far ends of the spectrum and draw inspiration.

In Sydney, beneath the widened M4, Under the Viaduct delivered a 1.5-kilometre-long community space to connect neighbourhoods previously fragmented by the highway, enlivened with bright colours and bold graphics. And as part of the M6 Stage 1 enabling works, McCarthy-Ador Reserve and Parklands has given residents of the Bayside Council upgraded playgrounds, sporting fields and public amenities. With these projects, the infrastructure in question is still in use while the context around it has been transformed from utilitarian to urban amenity.

Outside of the context of new infrastructure projects, we should be exploring other ‘easy’ wins—places that are already available and able to immediately generate new public space. Like in cities around the world, Sydney has its fair share we can start with, including:

  1. Western Distributor lower level at Sussex Street
  2. Eastern Distributor Bourke Street entry
  3. Wynyard and St. James abandoned rail tunnels
  4. Railway Square underpass (Australia’s first rail tunnel, dating to 1855)
  5. The Harbour Bridge south-eastern tramway portals
  6. Disused Sydney Monorail stations

With each new project, there are opportunities to transform the urban experience—minor interventions can have major impacts!

This is the second piece in a series where we are unpacking and exploring the role of design in delivering successful infrastructure projects.

Author: Dr Michael Kahn, Senior Urban Designer, DesignInc Sydney.


  1. Of course, this is not true of all cities or areas of cities. When large master-planned districts are developed, there can be a conscious effort to avoid the creation of dead space. But these are the exception, rather than the rule, with the organic city, built in a piecemeal fashion over decades or centuries, more often than not has an abundance of this liminal space.
  2. Caroline Schelle, ‘Push to transform the ‘desolate’ spaces beneath Melbourne’s roads and rail’, The Age, 24 July 2022,
  3. There are many metrics by which to judge success of projects, but by popularity—the number of users— capitalistic viability—the property values of surrounding development—and accolades—the number of awards—its success is pretty clear in a capitalist context; of course, this has been at the expense of other metrics such as affordability. Brenton Gibbs, ‘High Line New York – When Success Means ‘Failure’’, The Urban Developer, 1 May 2017,
  4. NSW Government, ‘City shaping vision for Central Station full steam ahead’, 22 August 2022,
  5. Notable examples include the Atlanta BeltLine (2006), the Sydney Goods Line (2012), Manchester’s Castlefield Viaduct Sky Park (2022).
  6. NSW Government, ‘NSW Rail Trails’, accessed 15 August 2022,
  7. One of the most dramatic examples of this is the Bordeaux riverfront at Quais Rive Gauche de la Garonne, which was transformed from car park to public park; David Bravo Bordas, ‘Restoration of public spaces on the left bank of the River Garonne’, Public Space, 2 May 2018,
  8. The Boston Big Dig, the Madrid Río project, Alaskan Way in Seattle and Klyde Warren Park in Dallas are all examples of undergrounding formerly at-grade or elevated roads. The Embarcadero in San Francisco and the Cheonggyecheon project in Seoul are examples of full removal of highways in favour of local roads and greenspace—and in Seoul, the restoration of a formerly undergrounded stream.
  9. The NSW Government has proposed the Cahill Expressway across Circular Quay be turned into an aerial park (like the High Line); Michael Koziol, “’We’d be nuts not to’: Stokes wants budget to fix ‘awful’ Circular Quay”, Sydney Morning Herald, 30 April 2022, The City of Sydney has advocated for its full removal as part of a sweeping suite of urban projects; Megan Gorrey, ‘Parks, pools and piazzas: Push to make Sydney in 2050 a place for people’, Sydney Morning Herald, 2 April 2022,
  10. Baltimore’s Inner Harbor project began in 1968, sparking similar projects around the globe over the subsequent decades, including the Docklands in London, Pier Mauá in Rio de Janeiro, Darling Harbour in Sydney, Docklands in Melbourne and Southbank in Brisbane—many of these projects are now going through their second round of regeneration; Richard Marshall, ed., Waterfronts in Post-Industrial Cities (London: Taylor & Francis, 2001).
  11. Hong Kong’s Kai Tak Airport closed in 1998, with ongoing transformation into a mixed-use precinctt; Berlin’s Templehof Airport closed in 2008 and is presently used as public parklands, with plans to develop a portion as apartments; Istanbul’s Atatürk Airport closed earlier this year, to be replaced by parklands.
  12. The Cisternerne sits beneath Søndermarken Park in Copenhagen, while the ancient Roman Bazilika Sarnıcı’ is just one of several hundred cisterns that remain in Istanbul.
  13. City of Sydney, ‘History of Paddington Reservoir Gardens’, 27 March 2013,
  14. Park(ing) Day, accessed 15 August 2022,
  15. Janette Sadik-Khan and Seth Solomonow, Streetfight: Handbook for an Urban Revolution (New York: Viking, 2016).