Reading about possible DRL alignments, there's an article in
The Overhead Wire on
Twin Cities Alignment Madness and the Perfect Network that makes for interesting reading as well. See this
link. It talks about the use of freight railway lines as alignment for transit. Especially when they were built originally to serve industrial areas.
The Overhead Wire said:
If you learn one thing from this post. Connecting people to dense employment drives transit ridership, so run the transit from where the people live to where they work in the highest densities. No brainer.
Ok, while TOW's conclusions is something of a truism it ignores that, at least in the North American context, most rapid transit riders connect from some other kind of transit (bus, park-n-ride, streetcar...) and, with a few exceptions, walk in ridership isn't particularly significant.
That doesn't completely obviate TOW's point drawing lines on a map and disregarding everything else will usually result in sub-optimal routes, but a route doesn't have to pass (in the most expensive manner possible) right through the most dense employment or residential clusters in order to serve those clusters.
Also, in your typical North American post-WW2 urban area (
Toronto included), density clusters are usually not even arranged in a way that would allow obvious corridors.
In planning any rapid transit line several things have to be considered; immediate residential/commercial density, ability to connect to other forms of transit, potential for redevelopment or future intensification and so forth. Likewise, all of those have to be balanced against cost.
Take the Junction. We could imagine a DRL station either being placed at Dundas and Keele, which would presumably draw the most local ridership, or we could imagine one placed a few hundred meters to the East in the rail corridor. The rail corridor station probably wouldn't have much lower ridership ultimately because it would be just as convenient for transfer riders. Marginally, it's unlikely a station at Dundas and Keele would attract enough riders to justify it's premium.
Similarly, even stations built in the Allan Expressway usually aren't much lower ridership than their Yonge counterparts.