Toronto commuters will have to wait until at least 2031 to ride the futuristic new Ontario Line subway, though construction progress is already apparent for the massive new Exhibition Station terminus at the southwest end of the 15.6-kilometre, 15-station transit line.

Metrolinx has shared an update on its ongoing early construction work at the station site, where the transit agency is preparing to build an impressive new multimodal hub linking the Ontario Line with the existing Exhibition Station serving GO trains.

The active GO station makes this a particularly complex operation, and much preparation has been undertaken to ensure Ontario Line construction and existing rail traffic can coexist.

Metrolinx opened a temporary entrance to the GO station this past summer, while a new permanent station entrance is currently well under construction on Atlantic Avenue to the north — to connect with a 40-metre extension of the existing passenger tunnel under the tracks.

The most visible change in recent months has been the construction of a temporary pedestrian bridge over the rail corridor linking the Exhibition side of the tracks with the Liberty Village side. Most recently, 50 cubic metres of concrete was poured to form the bridge's deck.

Set to open next spring, Exhibition Station's new bridge should prove especially useful during the station's busiest weeks in the summer, when the tunnel below the tracks is known for notorious congestion with CNE traffic.

The bridge will remain in place for several years, until the Ontario Line enters service.

GO passengers will also see short-term upgrades to accommodate construction, most notably new upgrades on the station's south platform that will pave the way for future Ontario Line-related work.

This new temporary GO platform — which will feature added pedestrian shelters — will require a realignment of some track sections running through the station.

All of this work will prepare the existing GO station for the largest transformation in its history, dating back to its origins as a Grand Trunk Railway stop in 1856.

Once all is said and done, both GO and Ontario Line tracks will be served in an enormous above-ground shared concourse that promises to be a jewel in the regional transit system's crown.

The completed multimodal station is expected to relieve crowding at Union Station by about 14,000 passengers (14 per cent) during rush hour.