Expo Line - Surrey Langley Extension: Planning & Pre-Construction

[aberdeen5698]

Originally Posted by swimmer_spe

Is there a way to get a high enough bridge in that area to prevent this??

Not cheaply. Rail lines can only tolerate a 2% grade, so the approaches need to be much longer. That would be very expensive and also likely problematic given the built infrastructure around the rail right of way on both sides of the river.

[swimmer_spe]

Originally Posted by aberdeen5698

Not cheaply. Rail lines can only tolerate a 2% grade, so the approaches need to be much longer. That would be very expensive and also likely problematic given the built infrastructure around the rail right of way on both sides of the river.

What about a tunnel then?

[CanSpice]

Originally Posted by swimmer_spe

What about a tunnel then?

Same problem, but now instead of having long approaches going up to a bridge you have to dig long approaches going down to a tunnel.

[Aroundtheworld]

Originally Posted by aberdeen5698

Not cheaply. Rail lines can only tolerate a 2% grade, so the approaches need to be much longer. That would be very expensive and also likely problematic given the built infrastructure around the rail right of way on both sides of the river.

Even 2% is generous. For fully-laden cars carrying mineral ore, the maximum grade is 0.5%. (I used to work as a rail engineer)

[VancouverOfTheFuture]

realistically, you would need something like the spiral tunnels. either going up, above ground taking up a crazy amount of space. or under ground, taking up a huge amount of money.

either way, it wont happen due to money.

[swimmer_spe]

If a tunnel or a high bridge is out of the question, what up river needs ships?

[aberdeen5698]

Originally Posted by swimmer_spe

If a tunnel or a high bridge is out of the question, what up river needs ships?

I can't say specifically. Something I've always wondered, though, is whether or not a slightly higher bridge might significantly reduce how often it has to be opened. A lot of the traffic is tugboats and other relatively small vessels that could probably get under the bridge, even at high tide, if it were just 20 or 30 feet higher. I'd hazard a guess that there might be an 80/20 tradeoff here - for something like 20% extra construction costs you might avoid 80% of the delays due to marine traffic.

[Trainguy]

Originally Posted by aberdeen5698

I can't say specifically. Something I've always wondered, though, is whether or not a slightly higher bridge might significantly reduce how often it has to be opened. A lot of the traffic is tugboats and other relatively small vessels that could probably get under the bridge, even at high tide, if it were just 20 or 30 feet higher. I'd hazard a guess that there might be an 80/20 tradeoff here - for something like 20% extra construction costs you might avoid 80% of the delays due to marine traffic.

Federal law states that any fixed span over a shipping lane has to be at a minimum height at high tide. I think around 44m is the number.

The problem with the New West bridge is that there are multiple diverging tracks right at each end of the bridge. The cost of adjusting all of those to make a higher bridge is cost prohibitive.

[swimmer_spe]

Originally Posted by Trainguy

Federal law states that any fixed span over a shipping lane has to be at a minimum height at high tide. I think around 44m is the number.

The problem with the New West bridge is that there are multiple diverging tracks right at each end of the bridge. The cost of adjusting all of those to make a higher bridge is cost prohibitive.

What is up river that makes it a shipping lane? Could that designation be removed?

[Migrant_Coconut]

Originally Posted by swimmer_spe

What is up river that makes it a shipping lane? Could that designation be removed?

Apparently, there's cargo traffic as far upstream as Maple Ridge.

[swimmer_spe]

Originally Posted by Migrant_Coconut

Apparently, there's cargo traffic as far upstream as Maple Ridge.

Doesn't list the terminals, just that it is a shipping channel.

[aberdeen5698]

Originally Posted by Trainguy

Federal law states that any fixed span over a shipping lane has to be at a minimum height at high tide. I think around 44m is the number.

I'm not talking about a fixed span, I'm talking about a slightly higher swing or lift span. Yes, you'd need to elevate the approaches too, but if you didn't raise it all that high you might be able to keep the cost to a reasonable level while substantially reducing the need to open the span for marine traffic.

There's really no pressing need to do this right now, but I'm just wondering out loud...

[Trainguy]

Originally Posted by aberdeen5698

I'm not talking about a fixed span, I'm talking about a slightly higher swing or lift span. Yes, you'd need to elevate the approaches too, but if you didn't raise it all that high you might be able to keep the cost to a reasonable level while substantially reducing the need to open the span for marine traffic.

There's really no pressing need to do this right now, but I'm just wondering out loud...

The second narrows CN bridge seems higher than the New West one and is a center lift bridge. The tugs that pull the barges would need a lot more clearance than would be feasible imo. If the marine traffic were super busy, I am sure they would come up with a fix so the railways don't suffer financially from it.

[AMTDGT]

Originally Posted by Trainguy

The second narrows CN bridge seems higher than the New West one and is a center lift bridge. The tugs that pull the barges would need a lot more clearance than would be feasible imo. If the marine traffic were super busy, I am sure they would come up with a fix so the railways don't suffer financially from it.

we used to have a sail boat that need a lift from the CN bridge on anything more that half tide.
There is more pleasure traffic under the CN bridge than the New West one, but there still is some

[Firebrand]

Is there a railway thread in this sub-forum? It seems that we’ve deviated so far it’s no longer related to the main topic of this thread.

[fredinno]

Originally Posted by Aroundtheworld

Even 2% is generous. For fully-laden cars carrying mineral ore, the maximum grade is 0.5%. (I used to work as a rail engineer)

Assuming the tunnel (or as suggested, new rail bridge with a lifting span) has a 25 m clearance (the George Massey Tunnel is 22m deep, and Port Mann is 42m clearance for comparison), the 5 km leadway would start @90 Av for the Surrey South Spur.

Definitely possible without making a spiral staircase- though probably best to make it a tunnel to avoid blighting the surrounding area.

Full 42m clearance is probably impossible economically, though, since the tunnel would start beyond the Alex Fraser- at that point, you're tunneling a quarter of the entire rail system.

Maybe we could have two tunnels, one for higher-grade traffic, and keep the old bridge for lower-grade traffic?

Originally Posted by Firebrand

Is there a railway thread in this sub-forum? It seems that we’ve deviated so far it’s no longer related to the main topic of this thread.

There's a commuter Rail Thread.

[BirchTrain]

https://www.surreynowleader.com/news/wha...lls-for-refreshed-plans-after-lrt-nixed/

The revitalization of Newton was centred around LRT. Now that it is effectively cancelled, the BIA is trying to figure out what will happen next. I think the "revitalizations" should go ahead, such as expanding the library. You don't need LRT for that.

Doug Elford will be trying to get BRT for the area and the rest of Surrey, which Translink is also supportive of.

[Aroundtheworld]

Originally Posted by fredinno

Assuming the tunnel (or as suggested, new rail bridge with a lifting span) has a 25 m clearance (the George Massey Tunnel is 22m deep, and Port Mann is 42m clearance for comparison), the 5 km leadway would start @90 Av for the Surrey South Spur.

Definitely possible without making a spiral staircase- though probably best to make it a tunnel to avoid blighting the surrounding area.

Full 42m clearance is probably impossible economically, though, since the tunnel would start beyond the Alex Fraser- at that point, you're tunneling a quarter of the entire rail system.

Maybe we could have two tunnels, one for higher-grade traffic, and keep the old bridge for lower-grade traffic?

There's a commuter Rail Thread.

Tunnel makes more sense as it would be going downhill fully-laden which permits at 1.5% grade, higher than the 0.5% if it was going uphill.

[Alex Mackinnon]

Originally Posted by Aroundtheworld

Tunnel makes more sense as it would be going downhill fully-laden which permits at 1.5% grade, higher than the 0.5% if it was going uphill.

It has to go uphill at least one direction...

Tunnels work better because they generally aren't as deep as a bridge would be tall. That particular point in the river at Pattullo is very deep though.

[Colin4567]

Originally Posted by Aroundtheworld

Tunnel makes more sense as it would be going downhill fully-laden which permits at 1.5% grade, higher than the 0.5% if it was going uphill.

I love it - we went on topic for 2 seconds but thanks for dragging us back from the main theme!