andrewpmk
Senior Member
So is building subways under strip malls and single family homes, but you have no issue supporting those.
I would run it in a tunnel until just north of Lawrence, and then have it hook up with the Richmond Hill line. The existing RH track would basically be abandoned south of Lawrence, used only for VIA movements.
And here's the issue with building the DRL as a subway line: even if the wildest fantasy plans, it only goes as far as Sheppard. Because it's a specific rail gauge and a specific vehicle, it can't run on 'traditional' rail. I'd much rather build a slightly more expensive tunnel that can interface with traditional rail lines on either end. That way, the potential routings into the suburbs are endless (branch to Pearson, branch to Unionville, branch to RHC, branch to Square One if the appropriate tunnel is built).
By narrowing it down to current subway technology that's incompatible with traditional rail, you effectively limit the reach of the relief to however far you build the subway. With RER, the track/signal/electrification upgrades at both ends of the tunnel will already been taking place, so the biggest question is "where do we route it to?". The potential for relief is far, far greater than anything a subway, unless it has a blank cheque, could ever accomplish.
I realize that tunneling anything is expensive, but building a tunnel large enough for double decker trains and platforms long enough for 12-car GO trains increases the cost dramatically. That is why the "SmartTrack" proposal died. The ridiculous western portion of "SmartTrack" would have cost far more than a subway. It might make sense to build underground commuter rail in a few cases like Crossrail or RER (though the Crossrail trains are not double decker) but the costs of that are astronomical compared to the DRL.
I don't think that there is a shortage of demand for a subway on Don Mills. This line could easily have demand similar to or slightly higher than Line 1. My proposal goes up to Don Mills/Finch, which is 2km north of Sheppard and connects to Seneca College. It is going to be really expensive - at least $10 billion, probably far more than that if the western extension to Dundas West is built - but it is absolutely necessary. Building a tunnel large enough for double decker trains would be prohibitively expensive and few cities have done this.
Going up the Richmond Hill line does not make sense because (a) there is little development along it north of Sheppard and south of Highway 7 and (b) the northern end of the Richmond Hill line is owned by CN. There is a lot more development along Don Mills in the area between Sheppard and Finch.