Designing a Resilient Transit Line for a Changing Climate

A new 10-mile subway line will reshape mobility in a major North American city. With 15 new stations and faster travel times, the line is designed to shift tens of thousands of daily trips away from cars, improving air quality while expanding access to key destinations. For owners, constructors, municipalities and design partners, the next question was straightforward: how do you protect an investment of this scale as climate conditions shift over the coming decades?

Project leaders chose to address climate risk early, while design options were still open and adaptation measures could be integrated without disrupting schedules or budgets. Onterris joined the delivery team to evaluate future-facing hazards and translate them into design and operational actions that construction partners could execute with confidence.

Across eight major climate risks, Onterris assessed mid to long term performance with a focus on the 2050s through 2080s. The team looked beyond a single threat and treated resilience as a system challenge, where stations, tunnels, entry points and supporting infrastructure all interact with municipal networks and operational realities. The assessment converted climate hazards into buildable decisions for designers and constructors: enhanced drainage and fortified entry points for flood resilience, thermal stress protections for underground stations in extreme heat and reinforced above-grade access areas for high-wind events.

Resilience only works when the full delivery chain owns it. Onterris used the Public Infrastructure Engineering Vulnerability Committee (PIEVC) framework, which aligns with International Organization for Standardization (ISO) 31000 risk management principles, to provide a rigorous and auditable basis for evaluation. Just as important, the process brought stakeholders together across design, construction, operations and maintenance so decisions reflected real constraints in the field and real expectations for long-term operation.

Onterris also focused the team on interdependencies with existing municipal systems, including stormwater networks. That coordination reduced the chance of solving one vulnerability while unintentionally creating another, especially where new infrastructure interfaces with legacy assets beyond the project boundary.

Not every risk can be eliminated through design alone. Where residual risk remained, Onterris worked with stakeholders to shape operational and maintenance strategies that keep assets resilient as conditions evolve. The recommendations supported asset management and capital planning so owners can sustain performance across the project life cycle, not just on opening day.

Over a year of site visits, workshops and structured assessment, the team moved climate resilience from a standalone study into a set of practical actions that fit the realities of transit delivery in Canada. The result is a clearer pathway for constructors, municipal partners and designers to build infrastructure that holds up under future conditions while supporting reliable low-emission mobility today.

For major rail lines and transit and road programs, climate resilience is increasingly a delivery requirement, not a future enhancement. This project shows a repeatable approach: assess hazards early, align the full delivery team and convert risk into adaptations that contractors can execute and operators can sustain.