The expansion of Union Subway Station will add a much-needed second subway platform at the station and improve the flow of TTC, GO Transit and tourist traffic through the area. It will provide additional passenger capacity, improve safety, make the station fully accessible and streamline the operational efficiency of the TTC Union Station Subway.

The second platform is also needed to accommodate the increased number of passengers who will someday soon live and work in the West Don Lands, East Bayfront and the Port Lands.