Quote:
Originally Posted by scryer
Isn't that more expensive? Because I wouldn't hold my breath on centre platforms.
Not that I'm saying I don't want it done right, etc, etc. Just saying that it might not be realistic to expect centre platforms for the underground portion.
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If they run twin bores, then the two tunnels need to have separation from each other. That separation - as was done with Canada Line downtown - is the width of the centre platform. Centre platform only needs one elevator to the platform and there may be fewer escalators (2 versus 4). That could cut down station costs. A centre platform may also make a 2nd station house more affordable (i.e. centre platform with 2 station houses can have the same number of elevators and escalators as side-platform station with one station house)
I doubt they would do a single bore like Evergreen, just because of the sinkhole delays they encountered on that one (though the soils are different).
For elevated stations, the advantage of the side platforms is the expensive guideway is kept straight. But if you are already doing twin bores, you've made that decision, so they'd likely go with the cheaper station option (centre platform).
Quote:
Originally Posted by VancouverOfTheFuture
keep in mind the document is 1y old and things do change and can change with these projects.
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Agreed.
Even the reference to the twin bore says "assumes..."
This is just the reference alignment - which, for Canada Line was also a bored tunnel and for Everegreen was also a twin bore.
The bidders may think outside the box.