BurlOak
Senior Member
Sounds good, or at least practical. The riders get some early benefits from the surface SmartTrack Phase 1, and then it should be a bit easier to collect funds for the expensive downtown tunnel.
I think there are 3 options:
a) Separate tunnels for SmartTrack and DRL; quite expensive.
b) A combined tunnel, but with separate pairs of tracks as you mentioned. This should result in substantial savings compared to (a), but require robust coordination between the two projects.
c) I would even consider the option of sharing the same pair of tracks between SmartTrack and DRL. Obviously, DRL will have to use mainline-compatible track width and rolling stock in that case. I imagine that such DRL will split off SmartTrack in the Pape & Queen area, continue north in a tunnel, and connect to Danforth subway at Pape or Donlands. It would continue north-east mostly tunneled, serving Thorncliffe, Flemmington, Eglinton & Don Mills. Further north, it could switch to surface Bala Sub (RH GO) corridor just north of Lawrence.
Option (c) should be the cheapest for downtown tunneling, but may incur higher costs further north as the mainline rail tunnel has to be wider than subway tunnel. I am not sure if it is cheaper or more expensive overall.
I am not sure about any savings from a combined tunnel. For subway, 2 - 6.8m diameter tunnels are needed. For subway and train, 2 - 9.5m diameter tunnels are required (assuming GO train same size as subway). This means that the track alone would take up 19m - or about 6 traffic lanes. However, the street is only 4 lanes wide, and you still need space for platforms. I do not think you could fit 4 tracks along Wellington, unless you stack 2 on top and 2 below - but I would not want to tunnel that deep because cost would go up significantly.
I would think that separate DRL on King (or north) and GO on Wellington would actually be the cheaper solution.