Cities are often described by what stands aboveground. Yet some of their most important stories lie beneath them.

Generations of growth have created layers of infrastructure that support modern life. Today, those layers present a challenge. As electrical demand continues to rise, utilities must strengthen reliability, add capacity and prepare for the future in places where space is limited.

That work is rarely straightforward. Beneath many cities lies a patchwork of aging utilities, abandoned infrastructure, undocumented modifications and incomplete records. What appears simple during planning can quickly become more complex once construction begins.

Building tomorrow's grid requires utilities to work within the constraints of yesterday's cities.

Power interruptions that may have once been considered manageable may affect hospitals, universities, transportation systems, businesses and critical community services. For many utilities, modernization efforts are now focused on creating greater system redundancy and flexibility.

The Watson Substation in Pittsburgh, Pennsylvania, illustrates this shift. This $237.4 million facility is a major power hub set to improve system resiliency and reduce outage risk as part of Duquesne Light Company’s (DLC) commitment to investing $2.7 billion within the next five years. Developed to strengthen reliability for the city's downtown Golden Triangle, the project introduced an additional source of power to one of the region's most important economic and institutional corridors. The facility established a third transmission source for downtown Pittsburgh and integrated high-voltage transmission, gas-insulated switchgear, transformers and expanded distribution infrastructure within a compact urban site surrounded by active streets, businesses and community institutions. Beyond the substation itself, the project included nearly 4.5 miles of new underground duct bank, the installation or reconstruction of 68 manholes and 162,000 circuit feet of distribution cable beneath active city streets. Together, these upgrades added capacity, operational flexibility and reliability to support continued growth in an area that serves major healthcare, education, commercial and civic institutions.

Unlike projects built where infrastructure can expand alongside new development, the Watson Substation required new electrical infrastructure to be woven into an already active urban environment. Every construction activity had to account for existing utilities, transportation infrastructure and the surrounding community while maintaining service for customers throughout downtown Pittsburgh. Close coordination among utility stakeholders, engineers, procurement personnel, constructors and local agencies helped the project move forward despite those constraints.

"Projects like Watson demonstrate what can be accomplished when planning, engineering and construction come together," says Marty Erdley, projects manager in the Transmission & Distribution Group at Burns & McDonnell. "The earlier project teams engage utilities, community stakeholders and operations personnel, the better equipped they are to anticipate challenges, make informed decisions and keep projects moving forward.”

The substation represents a broader trend playing out across cities nationwide: Finding ways to deliver modern electrical capacity in environments where land is scarce, development is dense and existing infrastructure already occupies much of the available space.

Unlike greenfield development, where project teams begin with a relatively blank slate, urban construction frequently requires navigating decades of previous activity. Pittsburgh's underground corridors contain more than a century of utility improvements, many of which are unmarked, mismarked or not accurately reflected in existing records. Former building foundations, abandoned utilities, undocumented infrastructure and disturbed soils can create conditions that remain hidden until excavation begins. Crews working on Watson Substation, for example, encountered unmarked underground utilities on a near-daily basis while extending circuits from the new facility. Each discovery required the team to pause, identify what had been uncovered and determine how to safely proceed while protecting workers and keeping the project on schedule. In cities where infrastructure has been added, modified and abandoned over generations, these unknown conditions can quickly pose some of the most significant challenges facing a project.

Underground construction for transmission, distribution and substation projects requires teams to account for both known and unknown conditions. While utility records, subsurface investigations and environmental reviews help reduce uncertainty, they cannot eliminate it entirely. Success often depends on a team’s ability to assess new information quickly, adapt safely in the field and keep work moving despite the unexpected.

In urban environments, infrastructure must coexist with a multitude of public engagements in spaces that may have longstanding cultural or historical significance. This shift has influenced how utilities approach design and construction planning and stakeholder engagement.

“On the Watson Substation, we worked closely with community stakeholders to understand what mattered most to the neighborhood and incorporate that feedback into the design,” Erdley says. “That collaboration helped us develop an architectural approach that reflected community priorities while still meeting the facility’s operational needs.”

Similar examples can be found across North America. Burns & McDonnell served as program manager for the Middletown-to-Norwalk transmission project in Connecticut, which included nearly 70 miles of new 345-kV transmission line, one of the longest transmission capital projects in the United States. The project impacted more than 7,000 private property owners and businesses across 18 cities and towns, requiring extensive coordination. On California's Tehachapi Renewable Transmission Project, a 173-mile high-voltage initiative connected wind farms in Kern County to Los Angeles and San Bernardino counties. The underground transmission lines crossed two major thoroughfares, multiple roadways, a shopping center, a flood control channel and a golf course. And in Ann Arbor, Michigan, Burns & McDonnell was selected to provide routing, site investigation and full engineer-procure-construct (EPC) services for the approximately 2.7-mile Apex-Phoenix 120-kV underground transmission project, carefully navigating a dense urban environment that includes the University of Michigan campus.

In New York City, the Dyckman-Hillside Substation stands as one of the original eight substations built by the city's rapid transit company between 1904 and 1905. While it continues to support transit operations today, the historic facility also serves as a workshop for elevators and escalators and provides backup equipment to support distribution needs during system disruptions. Its continued use illustrates how critical infrastructure can evolve over time, adapting to modern operational requirements while remaining part of a community's architectural and historical landscape.

The result becomes a more collaborative approach to infrastructure development where reliability and community considerations do not need to exist in opposition to one another.

As infrastructure projects become more complex, coordination becomes increasingly important.

Urban modernization efforts often involve utilities, municipalities, permitting agencies, transportation organizations, contractors, property owners and community stakeholders. Each group plays a role in project success, and misalignment or delays among them can have a significant impact.

For this reason, early planning and stakeholder engagement have become critical elements of project delivery. Successful projects typically establish communication channels early, identifying potential constraints and developing strategies for addressing challenges before groundbreaking ­— from coordinating permits, evaluating underground conditions and planning construction sequencing to maintaining ongoing communication with impacted stakeholders throughout the project’s life cycle.

Integrated delivery approaches, such as engineer-procure-construct (EPC), can help teams respond more effectively when unexpected conditions arise. Rather than pausing work while information moves between separate organizations, project teams can often evaluate conditions, develop solutions and make decisions more efficiently. Many utilities are turning to an EPC approach because of the value this integration brings in densely populated areas.

“Even with proper planning, there’s always going to be some level of uncertainty when you’re working in a dense urban environment,” says Michael Wagner, managing director in the Transmission & Distribution Group at Burns & McDonnell. “You can do your due diligence, review historical records and investigate existing conditions, but once construction begins, you must be prepared to adapt. The teams that are most successful are the ones that can respond quickly, collaborate effectively and keep construction moving productively when unexpected conditions arise.”

The Riazzi Substation, another DLC project, is tucked in the Oakland neighborhood of Pittsburgh, amid university campuses, medical facilities, research institutions and growing commercial development. Built on a constrained urban site about 1.5 miles east of Watson Substation, Riazzi replaced traditional substation approaches with a compact 138-kV gas-insulated switchgear (GIS) design that maximized available space while strengthening reliability. Designed to provide a more centralized power supply and reduce the risk of system overloads, the facility serves an area experiencing continued growth and increasing energy demand. Architectural treatments were incorporated to help the substation blend into the surrounding community, demonstrating how utilities are increasingly balancing operational needs with neighborhood expectations.

The pressures facing utilities are unlikely to diminish and expansion will continue to happen in urban cores. Planned developments will place additional demands on electrical systems, accelerating the need for infrastructure upgrades. New transmission lines, substations and distribution upgrades may all be needed to deliver power where it is needed most. In many cases, that work must occur within communities where generations of development have already shaped the landscape.

Whether projects involve new urban substations, upgraded underground distribution systems or modernization of century-old assets, the objective remains the same: Deliver reliable, resilient infrastructure that supports growth without losing sight of the communities they serve.

“The most successful projects are ones where teams can make informed decisions quickly, adapt to unexpected conditions and think creatively about how to work within the constraints that already exist,” Wagner says. “That kind of innovative problem-solving is what keeps projects moving forward and, ultimately, leads to successful outcomes.”