King Street underpass at the transit hub

[GtwoK]

That's exactly how it's being constructed. Foundations were dug out and poured first. Some early photos show the foundations poured - they look like a bunch of pillars overlapping slightly. I believe it was the same process used on the catenary pole foundations, albeit on a larger scale. The bridge deck was then poured on top of that. Finally, they're now excavating the entire thing. It's sort of like how some thing are casted out of metal, I suppose; an underground mold.

The one thing I'm not sure of is how they went from those overlapping pillars to the flat-faced walls we've got now.

[Canard]

They didn't - the pillars are off to the side and used to retain the earth on the sides. The walls were a separate dig/pour that occurred after the dome went up (ie; we didn't see it).

Constructing the bridge like this means the earth now being excavated did all the work of supporting the mass of the wet concrete, as opposed to having to build a massive support scaffold like you sometimes see with highway overpass construction. The support was already there - may as well use it.

[kps]

Mile 63: on Friday, there was a switch here, joining the northern track.

   

Also, there was a northern track.

[GtwoK]

Went somewhere I shouldn't have . You should be able to right click and Open in New Tab to see the fullsize versions.

Protip: the bridge is easy to climb up, but hard to get down from. May have sprained my ankle. That'll learn me.

[Canard]

I don't mean to sound like a jerk, but I think it's a very bad move to trespass and take photos inside a construction zone like that - no matter how incredible the photos are. It's not worth hurting yourself or getting into trouble over.

[GtwoK]

I was hesitant to do it, but while watching from the "safe" side of the fence, I noticed a considerable number of people using the construction zone as a shortcut from Moore to Victoria. Obviously 2 wrongs don't make a right, but I figured with that many people doing it, there must not be much "getting in trouble" going on, and risked it. Will take them down, if it eases your mind

[Rainrider22]

Went somewhere I shouldn't have . You should be able to right click and Open in New Tab to see the fullsize versions.

Protip: the bridge is easy to climb up, but hard to get down from. May have sprained my ankle. That'll learn me.

Great pics,  thanks for risking life and limb for us.

[Markster]

Thanks for the pictures!
It saves me the trouble of doing the same thing.

[Coke6pk]

While you were up on the bridge, did you measure to see how many tracks it could hold?

Coke

[panamaniac]

That picture from the bridge looking down King St is just amazing. Well done!

[GtwoK]

While you were up on the bridge, did you measure to see how many tracks it could hold?

Coke

I would assume just 2!

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[kps]

North side dome foundation being removed. Unlike the south side, which was broken up in place, they are using a hydraulic thingy (official technical term) to break off large chunks, and dragging them away to break up elsewhere.

       

[Canard]

I think that's because those blocks were just set in place, like patio stones.

[Viewfromthe42]

What's holding the active tracks in place? As they've removed the dome footings from the Victoria side of the underpass, and now what looks to be a surface dome footing from the Breithaupt side, I would imagine either you're leaving a lot of dirt in place to slope gently down from the active rail, under the underpass, to prevent any movement in those rails, or else you've put something to reinforce it in the ground (which will be broken after rails are moved).

Looking at it though, at this point, the rail bridge is structurally sound. Put a pair of switch tracks on either side, rails over the bridge, and you could take that old section out without much work, I would think.

[Canard]

That's probably the next step. As for holding the tracks, there are a ton of cylindrical concrete cylinders poured in the area to stabalize the earth, so I'd assume that's what's keeping the ground from shifting. Those would of course be dug out later. (Sooner?)