Before the current structure, an earlier Union Station was built in 1872 on Front Street between York and Simcoe Streets. The front of the old station was completed in 1895 and contained ticket offices, waiting rooms and railway offices. It was designed by E. P. Hannaford, Chief Engineer of the Grand Trunk Railway. The station was modelled on the Illinois Central Station in Chicago and had three domed towers, one containing a clock. In its time, the previous Union Station was considered to be one of the most modern and handsome stations on the continent. Its tall silhouette was a noted feature of the turn-of-the-century Toronto skyline.
Even though this station almost doubled the previous station in size, demands for an even larger station came soon after the completion. By 1911, the station handled some 40,000 passengers on more than 130 trains daily. The trainsheds were demolished in 1927 and 1928, and the station was torn down in 1931, four years after the present facility was officially opened.
Other than Penn in New York and the Rochester Station (which had a wonderful vaulted interior) the rest of these buildings look like Beaux Arts hackwork to me. Anything with columns stuck on it seems to get the nod from our American cousins.
Buffalo is actually not under threat anymore. It's been bought by the local preservation society, which has sealed it from the elements and now uses it occasionally for special events. They're still trying to figure out a permanent use for it.