It’s clear that Toronto needs more transit infrastructure–the Yonge line is overcrowded at rush hour, getting crosstown at the latitude of King and Queen St. is a major hassle, the Spadina LRT doesn’t quite work the way it’s supposed to, etc. Hence a proposal for new subways:
What I have in mind is a combination of traditional subway a la Bloor and Yonge lines, combined with LRT/streetcar routes that can be buried when they run through the core.
(1) Bury the Queen car between Roncesvalles and Broadview. For practical purposes, I think it would have to be east of Roncesvalles and west of Broadview, in order to avoid hopelessly complicating connections to the King car on those streets as well as access to Roncesvalles yard. Also need to think about the loop at Queen and McCaul. Keep the dedicated above ground lanes west of Roncesvalles. Probably nothing can be done east of Broadview without really messing with the neighborhood (but see  below).
(2) Create an Eglinton LRT. Bury it between say Bayview and Eg West with above-ground dedicated lanes east and west of those points. On a related note, I’ve never been entirely convinced about the St. Clair LRT. It’s supposed to improve service reliability but the Spadina experience isn’t altogether encouraging.
(3) Build a real honest-to-goodness Bathurst St. subway running from Bathurst and Steeles then downtown along say Adelaide St, possibly extending it as far as Adelaide and Parliament to serve St. Lawrence area (further eastern extension maybe to Coxwell along Eastern Ave. and then north?). Route some of the GO and York Region buses that currently feed into Yonge/Finch into Bathurst/Steeles instead. Reduce frequency on Spadina Line north of St. Clair W. Would require some major rejigging of St. Clair W. in order to establish a smooth connection, and delicate handling of Bathurst south of St. Clair to avoid disrupting streetcar connection between St. Clair and Hillcrest and Roncesvalles yards.
(4) I really don’t know what to do about the Sheppard subway… It doesn’t seem to be running at anywhere near capacity right now, and all it does is feed people into the already overcrowded Yonge Line.
Of course no one is willing to pay for any of this, but what do people think of the concept?