The City of Toronto has been growing twice as fast as the government expected, as growth elsewhere in the GTA rapidly slows. The bulk of this growth is concentrated in the Downtown core, putting even more strain on the streetcar network.
As Steve Munro said, there's no way that even an additional 60 new streetcars would meet demand. Furthermore, at some point in the next decade, we're going to have to start building the East Bayfront LRT. At that point, the number of peak streetcar customers using Union Station will have reached 10,000 pax in peak hour, which is nearly twice as high as the Crosstown's eastbound peak ridership, to put that in perspective. The City is asleep at the wheel here, and we can expect zero leadership whatsoever from Queen's Park. Both governments really need to wake up and realize what the hell is going on with Toronto's population growth.
In the meantime, if we're going to have a Downtown core that can meet population growth, we should consider the following:
1. Order an additional 130 streetcars, as Steve Munro said.
2. Build East Bayfront LRT and rebuild Union Station loop
3. Build the Relief Line West concurrently with the Relief Line North
4. Expand the network of streetcar priority corridors. College is the most obvious candidate, but Queen might work too.