The main entrance and façade faced the harbour facilitating transfers between boat travel on Lake Ontario and the railway.

As the Grand Trunk absorbed several smaller railways serving Toronto, passenger trains were increasingly consolidated at Union Station.

[3] In 1892, the railways agreed to expand the station through an extensive rebuilding program and Edmund Wragge was appointed the project's Chief Engineer.

The most distinctive feature of the redevelopment was a new seven-story office building on Front Street, built of red brick and Credit Valley stone.

The Great Toronto Fire of 1904 swept through the city's warehouse and manufacturing district, including the block immediately east of Union Station bounded by Bay, Front and York Streets.

The new Union Station headhouse and east and west office wings were completed in 1920, but didn't open to the public for another seven years while the railways and the city continued to argue over the approach tracks.