North Shore Rapid Transit | Park Royal-Metrotown via 2nd Narrows | BRT/RRT

[djmk]

Originally Posted by officedweller

Isn't the First Ave. hill east of Boundary pretty steep for a bus?

They could bypass 1st by going down Douglas rd

Boundary at Hastings is pretty steep as well.

[chowhou]

Originally Posted by djmk

They could bypass 1st by going down Douglas rd

Boundary at Hastings is pretty steep as well.

A Douglas Rd route is probably not happening now that Douglas Rd has been realigned with 1st.

Conceivably 1st could be flattened if they're able to buy out the properties at the top of the hill and cut down the hill between Macdonald Ave and Esmond Ave. No such thing is happening at Boundary though.

Both hills would be absolute disaster zones as soon as snow hits the ground.

[scottN]

Originally Posted by waves

https://www.google.com/maps/d/u/0/ed...Ag&usp=sharing

The rail bridge needs a vertical lift span to open the navigation channel for tall ships. If the highway / RRT bridge is above it, then there wouldn't be much room for the lifted span, unless the highway/RRT bridge is built extra tall.

[djmk]

Originally Posted by chowhou

A Douglas Rd route is probably not happening now that Douglas Rd has been realigned with 1st.

Conceivably 1st could be flattened if they're able to buy out the properties at the top of the hill and cut down the hill between Macdonald Ave and Esmond Ave. No such thing is happening at Boundary though.

Both hills would be absolute disaster zones as soon as snow hits the ground.

Douglas road jogs at Gilmour and continues a block north going past Steamworks Brewery (and my office!).

but still the problem remains at Hastings.

[jollyburger]

I guess that's why the original routing of the highway cuts away from Boundary..?

Crazy how much lighting the highway used to have



https://search.heritageburnaby.ca/li...scription45383

[djmk]

I guess it's possible. Its a bizarre road that starts at Canada Way and Sprott and ends at Boundary. And the Douglas Rd near Steamworks if a lot wider than it needs to be

[officedweller]

Originally Posted by djmk

They could bypass 1st by going down Douglas rd

Boundary at Hastings is pretty steep as well.

Yeah, Douglas would be better. The diagonal alignment on Douglas and less traffic could make up for the 2nd left hand turn.

[waves]

Originally Posted by scottN

The rail bridge needs a vertical lift span to open the navigation channel for tall ships. If the highway / RRT bridge is above it, then there wouldn't be much room for the lifted span, unless the highway/RRT bridge is built extra tall.

I thinking of a new vertical lift rail bridge then a separate highway RRT bridge. The hydro tower might need to be moved 50m east. Something like this:

[Migrant_Coconut]

Honest question: how many road-rail bridges have been built since the turn of the century, or are still used by urban lines? Seems like we're trending away from integration.

[Tvisforme]

Originally Posted by Migrant_Coconut

Honest question: how many road-rail bridges have been built since the turn of the century, or are still used by urban lines? Seems like we're trending away from integration.

I don't have an answer to that, but I would suggest that timing might have something to do with it. Locally, the SkyBridge and the North Arm Canada Line Bridge were built decades apart from the road bridges near them. It wouldn't have made sense to replace a functional bridge earlier than necessary just to combine it.

[madog222]

The Champlain Bridge would be one, they are definitely few and far between.

All these old road-rail bridges were built for feight railways, with privatization of the railways that won't happen now.

[Alex Mackinnon]

It also doesn't make sense from a design perspective. Trains, cars and truck have very different loadings and operating geometries. The bridges around here end need to have a large vertical clearance, which is hard for the trains to manage resulting in low-level bridges. Meanwhile car traffic prioritizes reliability and services levels, so high-level bridges are used to avoid marine traffic closures.

The train bridges also have to accommodate much higher loads.

Basically it makes it much more expensive to combine freight rail and road traffic than a single bridge would be.

[Kisai]

Originally Posted by Alex Mackinnon

It also doesn't make sense from a design perspective. Trains, cars and truck have very different loadings and operating geometries. The bridges around here end need to have a large vertical clearance, which is hard for the trains to manage resulting in low-level bridges. Meanwhile car traffic prioritizes reliability and services levels, so high-level bridges are used to avoid marine traffic closures.

The train bridges also have to accommodate much higher loads.

Basically it makes it much more expensive to combine freight rail and road traffic than a single bridge would be.

If I were to hazard a guess, the better reason to not "double deck" a bridge (or even a tunnel) goes back to the 1989 Cypress Freeway collapse during the 1989 Loma Prieta Earthquake. The last thing you want is a heavy vehicle falling through the deck and taking out something beneath it (such as a metro or a freight train) that can't stop on a dime. And yes, I'm aware, and have been on the Skytrain when it has stopped dead while in motion.

There are logical reasons why you can double deck a metro and a highway, because you need to be able to re-assign lanes for traffic, or close lanes in emergencies or for repairs, you can't have the train running down the center of it. The LIM Skytrain is capable of climbing grades that a more typical metro or commuter rail would not.

However if you wanted to combine this with freight, now the freight rail deck has to be taller and flatter. But then you also have the question of how you're going to do this and handle ship traffic.

The "back of the envelope" engineer design to me would be to actually stick the highway, metro and fright into the same ROW, but leave the freight rail bridge in the same place it already is, and have the metro/highway bridge simply elevated above it. Then also just shove the hydro lines into the bridge as a bonus feature since the RRT would need electrical service anyway.

[jollyburger]

Originally Posted by Kisai

If I were to hazard a guess, the better reason to not "double deck" a bridge (or even a tunnel) goes back to the 1989 Cypress Freeway collapse during the 1989 Loma Prieta Earthquake. The last thing you want is a heavy vehicle falling through the deck and taking out something beneath it (such as a metro or a freight train) that can't stop on a dime. And yes, I'm aware, and have been on the Skytrain when it has stopped dead while in motion.

There are logical reasons why you can double deck a metro and a highway, because you need to be able to re-assign lanes for traffic, or close lanes in emergencies or for repairs, you can't have the train running down the center of it. The LIM Skytrain is capable of climbing grades that a more typical metro or commuter rail would not.

However if you wanted to combine this with freight, now the freight rail deck has to be taller and flatter. But then you also have the question of how you're going to do this and handle ship traffic.

The "back of the envelope" engineer design to me would be to actually stick the highway, metro and fright into the same ROW, but leave the freight rail bridge in the same place it already is, and have the metro/highway bridge simply elevated above it. Then also just shove the hydro lines into the bridge as a bonus feature since the RRT would need electrical service anyway.

But the collapse of a double decker concrete freeway with design flaws that couldn't survive a massive earthquake isn't really comparable. If you are worried about that then the lower deck is just as likely to collapse into the water before anything on the second level hit it.

There is no way they are going to do anything construction wise that wouldn't allow them to have a seamless transition of freight traffic to a new bridge.

[VancouverOfTheFuture]

Originally Posted by Kisai

Then also just shove the hydro lines into the bridge as a bonus feature since the RRT would need electrical service anyway.

that doesn't really work. the transmission lines crossing the inlet have no relation to the power for SkyTrain. the voltage is wrong, and the current is wrong. it both needs transformers to step it down, and a rectifier station to change the current. there is no reason a bridge cant have the transmission lines since the Massey Tunnel has high voltage transmission lines running through it.

the south side could be played around with easy enough. you just need gradual sloping, long tunnels for the railway, and moderate tunnels for SkyTrain. the electrical lines can handle anything as well as traffic. but on the north side, i dont see how the railway would accept a higher bridge since its much lower there. there would need to be some major railway viaducts. there is also a rail yard close to the crossing which would need to be accounted for.

realistically the railway isn't moving/changing. only the road and electrical can.

[waves]

Agreed that the heavy rail can't really move up or down, but it could be moved to the east or west with a new bridge if needed. I also agree that neither combining it with the Highway, nor the Skytrain seem realistic.

There are a number of examples however of Road+Light Rail Combo bridges; the double decker Dongshuimen Bridge in China that has a lower deck for metro and an upper deck for cars:


Source: Reddit r/infrastructure

The Tsing-Ma bridge has a lower deck for the Hong Kong airport metro and the main span is 1,300m long and 200m high:


Source: Checkerboardhill Blog

The 25 de Abril Bridge in Lisbon Portugal is interesting because the bridge was originally designed for the metro but because it was too expensive at first they cut it from the project. Years later, they changed their mind and then retrofitted the bridge to accommodate the rail lines:


Source: lisbonlisboaportugal.com

[Kisai]

Originally Posted by VancouverOfTheFuture

realistically the railway isn't moving/changing. only the road and electrical can.

When you can move things into one ROW, what is created is a single point of failure.

The point I was trying to make is that you can put everything in the same ROW, but it doesn't have to be the same structure.

Like you could put freight on a bridge that either turns or flips open, then 80 meters above that you have a fixed bridge that carries the metro, and then 5 meters above that you have the road bridge, and then run hydro's lines insulators 5 meters up and outwards (so a failure doesn't send the lines into the bridge deck before breakers can trip.) You could also do the same with gas or water lines, though there are different difficulties with pumping uphill that don't exist with electrical services.

It's not an advocation to DO that, just that there is nothing physically preventing sharing the ROW, except not wanting to cause multiple service failures due to a single failure in the bridge structure itself. Like you could have Paved road surface on top of the rail ROW reserved for Emergency services or Bus-Bridge support that physically has gates or bollards at each end to keep it from being used as an alternate route.

[Tvisforme]

Originally Posted by Kisai

....Like you could have Paved road surface on top of the rail ROW reserved for Emergency services or Bus-Bridge support that physically has gates or bollards at each end to keep it from being used as an alternate route.

It's too bad that they don't have this setup for the existing Second Narrows rail bridge, so that transit could divert in the case of a closure.

[jollyburger]

^^ They could just install retractable rail gear on all the buses so you wouldn't have to pave the bridge.