Future of Design August 11, 2023

3 ways prefabrication can keep public transit projects moving

Public transit plays a vital role in moving people safely and sustainably, and transit systems need to flex and evolve to keep pace with the communities they serve. By extending existing routes and improving and maintaining stops and stations, cities can provide passengers with a high-quality, safe, and pleasant experience.

But providing these extensions and upgrades, particularly in busy train stations, can be costly for transit agencies and inconvenient for passengers.

Here are three ways that using prefabricated elements can help:
01. Minimize disruption

Given that public transit is typically located in busy urban areas, constructing new stops and stations can be disruptive, requiring officials to detour pedestrian and vehicular traffic for months. And maintenance and construction work at stations that are in active operation can be even trickier due to the need to keep passengers safe and trains on schedule.

Inconvenience can be dramatically reduced when components of train stations are manufactured in factories or workshops. Three stations along the Canada Line, for instance, opened more than three months ahead of schedule thanks in large part to prefabricated components that were manufactured off site while foundational civil work was done in situ. The builder was then able to ship the components to site and erect the majority of the station structure in record time.

“It's not like a conventional building where you can shut it down and the occupants of that building are temporarily accommodated elsewhere. We don't have that luxury.”
Marco Bonaventura, manager of facility design at TransLink Canada
02. Improve quality

Because prefabricated components are built by skilled workers in specialized settings, quality control issues are more likely to be noticed and addressed before the components leave the manufacturing facility.

“You’re likely to get a better fit and finish in a factory as opposed to trying to do it on site,” Bonaventura says. “There is an intent, especially on the more precious portions of our stations like the exposed structures, to have those parts be done in a controlled environment. They can be prepped and sub-assembled, if not completely assembled, off-site. That helps us meet our specifications on the qualitative side.”

Those qualitative specifications include aesthetics, which, in turn, have a strong impact on station users’ experience. “At Brentwood station we focused in on some key pieces, particularly the roof components,” Bonaventura says. “We optimized the process to create a unique shape, but we used standardized ‘off the shelf’ approaches.”

03. Reduce cost

Manufacturers of prefabricated components can take advantage of economies of scale, passing the savings on to transit agencies. And modular, prefabricated elements are quicker and easier to manufacture, install, maintain, and replace, resulting in lower costs over a building’s entire lifetime.

In fact, although a project’s initial cost can grab headlines and spur debate, ongoing maintenance expenses over a station’s lifetime can be just as significant. “The cost of sustaining the work beyond opening day is sometimes overlooked,” Bonaventura says. “So we try to embed maintenance efficiencies into our facility designs from the start, and modularity and prefabrication play a big part.”

Minimizing construction time during maintenance activities like repairing or replacing roof or wall panels is particularly important due to the disruption and safety concerns that arise when stations are in active operation. Thoughtfully designed electrical systems and other “behind-the-scenes” infrastructure can fit neatly within or behind prefabricated panels or other components, making access quick and easy. “Performing work on-site becomes very costly because a team of workers comes in while the rest of the station is still functioning,” Bonaventura says. “It’s a high-cost, high-risk situation, but we have to continue to operate.”

A pre-fab future

Bonaventura thinks more transit agencies are starting to see the benefits of prefabrication. “There’s been a lot of progress and refinement over the years, and we’re gaining a better understanding of the benefits and how to harness them, both for new station projects and upgrades to existing operating stations,” he says. “There will always be the need for site prep and other on-site work, but we’re trying to maximize and optimize the off-site construction and assembly and then minimize the work done on site.”