A major component of the Union Station renewal, the project consists of rehabilitating the existing network of historic steel arches and replacing the central area with a large glass atrium. Visible from the surrounding buildings, the roof is a dynamic architectural feature at Union Station which complements the heritage structure. The team worked closely with Parks Canada and ERA Architects to ensure the preservation of this national historic site.

Floating over the tracks, the atrium provides daylight at platform level and a visual connection from the station to the waterfront. Delicate curtains of clear glass louvers are suspended from the roof on a light network of steel tubes and cables to repel penetration by rain and snow while naturally ventilating the platforms. To reduce the risk of service interruption and delays during the construction over the operational tracks, the team implemented a sequenced implementation plan which resulted in a single pass of construction.