Extend the Finch LRT eastwards to Yonge, have it turn down Yonge and run at-grade to stimulate pedestrianization of the corridor, and then enter a tunnel portal near Sheppard and turn left to continue east through the Line 4 tunnel (now converted either with catenary for existing vehicles or new bi-mode catenary/third rail LRVs) until a portal near Victoria Park to bring it back to at-grade street operation until STC. Would pass Agincourt Mall which is slated for a big redevelopment, Agincourt GO which will be on the RER network, and obviously STC which is a growing city hub as well.
I think it would be a lot more cost-effective to develop south-central Richmond Hill into a new downtown like Vaughan's, since all the rail infrastructure you would need for that already exists. It would be much cheaper to either leave Line 4 with its current technology or convert it to a Crosstown-style LRT.
I'd much prefer keeping Finch and Sheppard as two separate routes. First, turning Finch into a crosstown LRT. Almost entirely on surface and not spectacularly fast, but that's OK because it will be 100% compatible with the existing bus travel patterns. People who take Finch W and Finch E buses today won't lose anything, they will have same service, only more reliable and somewhat faster. And, the construction won't involve much hurdles.
I think there's a lot of good that making any Sheppard extension more commuter/express. This could serve something of the same purpose that SkyTrain does with further stop distance than a traditional subway (which allows for much higher average train speeds).This is why I am leaning towards a reconfig of Line 4 to operate as a cheaper, nimble hybrid subway-commuter line
How/where would the Sheppard line go above ground, though, and what routes would it follow to the west/east?
Even earlier than that, one of the GO-ALRT lines would've used the Finch Hydro Corridor as well as the 401 corridor and would've provided headways as low as 2 minutes using fully automated trains.Random thing I found doing some digging for a slightly related project of mine. Apparently the idea of rapid trainsit running alongside the 401 to Durham isn't all that new. According to this map, during the Network 2011 days there was a plan (or idea at least) of a GO line (or regional equivalent) running between Durham and STC via the 401 and Kingston Road corridors.View attachment 270651
Just keep in mind that the 401 collector/express system doesn't extend past Neilson at the time this map is publishedRandom thing I found doing some digging for a slightly related project of mine. Apparently the idea of rapid trainsit running alongside the 401 to Durham isn't all that new. According to this map, during the Network 2011 days there was a plan (or idea at least) of a GO line (or regional equivalent) running between Durham and STC via the 401 and Kingston Road corridors.View attachment 270651
I think the options for above ground are mostly in the 401 corridor, and using that corridor makes sense for the outer sections only. We don't want to lose the density opportunities in the middle.
In the west, I'd suggest going mostly underground until Allen Rd; the West Don crossing may be on a bridge though because the valley is very deep. After connecting to Line 1 Sheppard West station, the line can turn south and continue at the surface level from Sheppard to Wilson.
Within Toronto there is a lot of opportunity to densify corridors like Sheppard or Wilson. Outside of Toronto it would likely be more oriented to commuters, and at some point one would expect density to find a place around those outer stations. Considering the branches to the west, if there is a branch to DT Brampton, we would have to choose a route that does not compete with the Kitchener RER (which I am not sure of a route). A Mississauga branch could follow highway corridors from YYZ all the way to Square One and potentially beyond. In the east, if we intend to extend the line beyond Pickering, it would compete with the Lakeshore RER so it may be worthwhile to use the hydro corridor or something north. Would also set it up to have a branch to the "Pickering Airport" when it gets built in the year 2076