Originally Posted by mrjauk
Given the large number of commuters moving between town centres (outside of downtown Vancouver), having the Evergreen line go from Coquitlam to Surrey makes sense.
Interesting idea, though I'd have to disagree pretty strongly with your setup. I realize you're trying to improve connectivity (i.e. by providing a one-seat ride) between Coquitlam and Surrey, but it's at the cost of robbing the system of higher capacities at the busiest parts. Specifically, the interlining in Surrey means Expo's pinch point (Broadway-Main St in the AM peak hour) and the interlining in Coquitlam means what will likely be the busiest part of the Millennium Line (Commercial-VCC in the AM peak) will both have much lower frequencies than they otherwise could. I think a better set-up would be to take advantage of the new Port Mann and run some rail from Coquitlam Centre to Surrey Centre that way instead. Not only could it provide a one seat ride, but it also serves an area that doesn't yet have higher order transit (i.e. Guildford).
From a technical standpoint though, I think it's possible, though the track geometry was never set up for this sort of thing.
You could probably do something at Lougheed, as both the existing Millennium Line and future Evergreen have a North-South route along North Road before both turning West to Lougheed Station. Building a bit of guideway to connect the two, with the appropriate track switches (or flyovers like at Bridgeport, if necessary). At Columbia, I suppose you could probably do something where the trains pull onto the Expo mainline, and then switch directions, and head over the SkyBridge. Although, this will significantly interfere with Expo Line frequency. The only other option would be to tunnel a giant U-turn under New West so the train can come turn around.
I'm also not entirely sold on the West End thing. As a downtown circulator, a tunneled system is pretty much useless. Station access time (getting from street level to platform level) would more than cancel out any time benefits of faster operating speeds (i.e., would anyone here bother taking SkyTrain from Burrard to Granville - even if it was free - when you can walk there faster?). For that sort of thing, a think the planned Streetcar would work a lot better.
Of course, a reroute of Canada Line or Expo Line to the West End would make it easier for people to travel between the West End and areas outside of downtown, but, again, it would come at the cost of diminished service quality for the region's #1 transit trip generator, the central buisness district. I'm not entirely sure the benefits outweight the (service quality) costs.