I've been working on a Gardiner Expressway teardown option in which a cable-stayed viaduct is constructed above the rail corridor to Spadina Ave. Wellington and Front would be converted to opposing one-way streets.
This concept can be viewed in more detail on Maps Engine.
Travelling Eastbound
-Through traffic would be instructed to follow Lake Shore Blvd and exit at the Jamieson interchange. Here, the Gardiner would be reduced from 3 lanes to 2 to travel on the viaduct.
-Exit ramp at Strachan Rd/Fort York Blvd.
-
Viaduct passes over the Bathurst Street Bridge.
-Exit ramp at Dan Leckie Way for access to CityPlace, Rogers Centre, CN Tower, and ACC. This exit would also be used to access Bathurst Street
-The Gardiner passes under the Puente del Luz
-Termination at Front/Spadina.
-Traffic through the core would be funnelled onto Spadina to Adelaide and other distributor roads. Right turns onto Spadina would be restricted due to the angle of the ramp
-Between Front and Blue Jays Way, Front would have 6 lane cross-section with 1 westbound and 3 eastbound lanes with left turn lanes and a parking lane on the north side. The road envelope has more than enough room for this. Front would then continue as a 3 lane one-way road with parking lanes to the intersection of Front/York where Front would be reduced to 2 lanes with parking lanes in front of Union Station. Remaining traffic would be directed onto University and York.
Travelling Westbound
-Wellington would keep its existing 4-lane cross section to Blue Jays Way. 2 lanes of Wellington would descend below ground at Clarence Square and continue to the rail corridor to access the Gardiner.
-Entrance ramp to the Gardiner at Spadina/Front. Front would be converted to a one-way westbound at Spadina to simplify traffic operation at this intersection.
-The Gardiner would then continue on be 2 westbound lanes travelling beneath the Puente del Luz and over the Bathurst Street Bridge
-Directional entrance ramp from Bathurst Street over the rail corridor, continuing as a cable-stayed viaduct
-Entrance ramp from Fort York Boulevard. From here, the Gardiner would then continue on its existing elevated structure.
This arrangement would require the Bathurst GO Yard to be decomissioned. It would still be possible to keep the Gardiner as an elevated cable-stayed structure over the yard, but at a significant cost increase. GO could get rid of the yard if it is to modify its operations to have more through-running routes, of if it were to relocate its yard to the West Don Lands.
Replacing the function of the Gardiner within the rail corridor has the significant benefit of freeing up much of the land currently occupied by the highway for development and eliminating the messy complex of ramps between Spadina and Yonge. By relocating the traffic flow in a remove scenario, it would no longer be necessary to widen Lake Shore Boulevard past 8 lanes. It won't be possible to widen Lakeshore where it bottlenecks at Bathurst. Compared to a tunnel option, it would be far less expensive and disruptive during construction. Tunnelling also makes selling off land formerly occupied by the Gardiner far more complicated. Given the choice between $5 Billion to tunnel the Gardiner along its current alignment or $2 Billion to elevate and run at-grade in the rail corridor, I'd rather spend money on building a Viaduct.
I see this as being feasible in about 20 years given the following conditions:
-DRL is constructed from Dundas West to Don Mills/Eglinton.
-A streetcar right-of-way is built on Fort York/Bremner Blvd connecting Exhibition to Union.
-GO changes its operating model to run frequent regional rail service, optimally using electrified rail corridors.
