Quote:
Originally Posted by queetz@home
So I guess it pretty much take them one night to put up a couple of steel guideway segments (I noticed from your video its two large pieces bolted together) for one lane?
Presumably, once the concrete has been poured on the support brace, then can proceed to put on the next two sections for outbound and inbound....so perhaps by March 1, they can be done?
Regardless, it will be very interesting to see how it would look like once they connect to the White Spot column. Seems the gap between the columns are so long, but as posted earlier, we have seen this kind of thing before in New West...
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Each of the curved steel elements from Lougheed Station to North road holds a single track, and the steelwork is needed because of the (now un-necessary) twist-over hump left over from the original construction of the Millennium Line. The hump was the beginning of the twist-over to keep outbound and inbound tracks on their proper sides of the North Road stations. With the twist-over removed, now trains running between Lougheed and Burquitlam stations will be 'wrong railing' ie: running on the left-hand tracks rather than the right-hand tracks as seen on the rest of the system.
Rather than spend a lot of time & $$ to re-engineer that section of track after the the twist-over was deleted, the tracks were simply left side-by-side through the curve. However, with two segments of the original hump already built, when adding the Evergreen extension the two pre-built tracks were already at different elevations, so the two steel curves are being used to continue the separated tracks, adjust for the different elevations of each track while they fly over White Spot, and then arrive at the median of North Road at the same elevation.
Once on North Road, the separate tracks on the steel beams become twin tracks on the concrete beams being installed using the gantry crane. (as seen in earlier photos)
A similar transition can be seen north of Broadway & Commercial Station:
The Expo tracks transition from the concrete track beams along-side the Grandview Cut, to separate steel beams in the curve over Commercial, then back to separate inbound and outbound concrete beams while moving apart from each other to make room for the Broadway platform.
Once the steel beams are in place and bolted together to make a solid unit, they will be capped with a concrete track base and sides (to hold the LIM, the train rails, and the power rails). This gives the impression at the rail-fan windows that everything is concrete, even though there is an underlying steel beam holding everything together through the curve over White Spot.
If you're wondering how they will transition from Left-hand running to Right-hand running for the rest of the Evergreen line, there are two cross-overs south of Burquitlam station to get trains back on their 'proper' Right-hand tracks.
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