Greenline over the Bow
 

Should the new Calgary Greenline go over the bow or under the bow?

If a bridge results in $500 million in savings over the tunnel option, it's the obvious choice.

Big if, IMO. It's going to be tunneling for a while north and south of there, so I don't fully believe that surfacing and building a high quality (expensive) bridge then diving into a tunnel again through the unstable bluffs will be cheaper. Sounds a lot more complicated to me, and complexity means cost.

And I say that as someone who has always thought the bridge would be a great option.

I think one of the major challenges with the bridge is how it tunnels once in downtown. Could be a big disruption to a street and neighbouring properties.

The biggest benefit I would see for a bridge is another pedestrian/bike access built with it. Other than that, I think the tunnel is probably overall a better choice. But I'm not an engineer. Both come with significant potentials for cost overruns.

Are you serious?!? I can't imagine a tunnel under the Bow costing more than half that much; maybe even half of that. It's definitely not the cost of a bridge, the two tunnel egresses and, 500 million!!!

Definitely. The half billion is for the full tunnel option, not just the river crossing.

I would like to see it go over The Bow.

Over for me.

rather see it go under

I could only answer if I could see how much one would save over the other, and what extra transit we could get for that money.

Fully agreed.

True, but if it is going to be a bridge, it should be a more efficient elevated line, so the point is moot.

Yes it would cost that much, especially when you consider how much extra length of tunneling it would require on the north side of the river if you sunk the train so deep. That means the incremental cost of tunneling below the Bow River is not just limited to the tunnels under the river. This has been extremely well documented. Surprised you are surprised.

This exactly for me.

Regardless of what happens, I am very excited for this amazing piece of people-connecting infrastructure!

Could it hover over a few blocks and then duck under? I see huge problems with that because of density, but who knows? You could combine it with the Sien Lok Park Redevelopment......or just do what Vancouver did and have the train go right through a newly constructed building......yeah right.

https://c1.staticflickr.com/1/176/40...acd_z.jpg?zz=1
https://c1.staticflickr.com/1/176/40...acd_z.jpg?zz=1

No offense but, I don't believe a word you say. It makes no sense that the difference in cost would be $500 million for less than a kilometre of tunnels even in Calgary's fractured shale.

It also hasn't been 'extremely well documented'. All the cost estimates so far are just that, rough estimates.

No offense taken, but if you "don't believe a word [I] say", why do you respond?

The increase in length of tunnels between options C and D are significantly more than a kilometer. Additionally, the increase in cost is not just all of the increased tunneling and related utilities for the tunnels, but also the way more expensive costs of the stations that would then be buried way further with option D. Virtually each and every piece increase in price substantially with the burial option.

Irrelevant though, because the only two options worth comparing are B and D. C will never be built.

Thanks. Now I understand. You once again decided to change the game to fit your agenda by introducing C when the discussion is about B and D. And, yeah, I felt it necessary to once again remind you that I don't believe a word you say.

$500 million + the cost of the bridge option for let's say ... a kilometre of tunnel is plain stupid.