[timio]

Blurry window pic of Torbram

 

[hw621]

Glad to see work proceeding. Can't wait to see centenary and quiet electric trains on the GO network, something my little town in Eastern Europe had 30 years ago. Long, long overdue change for GO.

So you have moved here for worse, lol, at least for the transit file...

 

[Neutrino]

So you have moved here for worse, lol, at least for the transit file...

Well, that entire part of the world fell apart in 1991 so we had no choice after a certain point. These days, every one back there has a car just like here thanks to cheap credit. But the roads in that part of the world were never built to handle such vehicle volumes and congestion is bad.

 

[Allandale25]

^ I think it was mentioned in the Davenport Overpass thread. @alexanderglista may remember.

 

[hw621]

^ Speaking of Agincourt, latest email update received today (pictures included).

Does any of these work include laying the power lines for future electrification?

 

[crs1026]

Does any of these work include laying the power lines for future electrification?

This document from the Electrification EA shows the conceptual plan for this line - 2 25-kv supply circuits. See also this.

I browsed a few of the EA documents, and while there was a lot of ambiguity, it appears that GO assumes the feeder lines will be part of the overhead system and not buried underground.

There has been a lot of work along the corridor with underground cabling and fiber conduits, but these appeared (to my layman's eye) to be telecom and not electrical in nature.

So I am doubtful that any infrastructure for electrification is included in the current work. Certainly, no footings for catenary poles.

- Paul

 

[robmausser]

Be prepared for a long wait yet.

No doubt. This work to be done in 2021? This barely scratches the surface.

^ Speaking of Agincourt, latest email update received today (pictures included).

I hope they accounted for these sound barriers being so close together! If not done right the sound can actually reflect off each side and amplify the noise.

 

[steveintoronto]

I hope they accounted for these sound barriers being so close together! If not done right the sound can actually reflect off each side and amplify the noise.

Good catch. You have an intuitive sense of acoustics and waveguides. There is a way to mitigate the 'channelling' of the sound, and they're not doing it, oddly. I've seen the technique used under bridges on the GO system, and I'll look for a well-explained and detailed article to link later, but basically the technique is to present an 'anechoic' surface on the wall such that it scatters longer wavelengths in a way that the disparate directions from scattering/diffusing tend to phase cancel if the proportions of the 'diffusers' are matched to the wavelength(s) to be subdued.

I can see very real problems if they copy the opposing wall with the same surface in the pic.

More later, sharp eye! The term for the concern is 'Standing Waves'.

Must run, but quick Google shows these results. Not mentioned that I see in the cursory perusal is 'slotting' which I'll discuss later.
https://www.google.ca/search?q=Para...19j0j7&client=ubuntu&sourceid=chrome&ie=UTF-8

I'm amazed the neighbourhood reps haven't raised this issue. That being said, as long as one opposing surface is 'treated', the other can remain as shown in the pic. The clincher will be what they raise the other side. The posts don't look promising for something anti-acoustically active.

Quick Edit to Add:

This is brilliant in so many ways:

By CECILE BORKHATARIA FOR DAILYMAIL.COM

PUBLISHED: 19:07 EST, 17 October 2017 | UPDATED: 20:39 EST, 17 October 2017

The bizarre 'origami' concrete barriers that could finally end the misery of road noise
Managing traffic noises is hard as vehicles produce a range of sound frequencies
Currently, only heavy, wall-like barriers can effectively dampen various sounds
But a new 'origami lattice' could potentially reduce acoustic noise on roadways
When researchers tested their prototype, it reduced acoustic pressure by 90%
The system relies on noise-diffusing cylinders that can be drawn closer together or farther apart to selectively dampen different sound frequencies

Scroll down for video (see vid link and pics at article)(see here: https://news.engin.umich.edu/2018/02/origami-sonic-barrier-could-reduce-traffic-noise/ )

Researchers have developed a new method, dubbed the 'origami lattice' prototype, that could potentially reduce acoustic noise on roadways. Pictured is a periodic pipe noise barrier installed in Eindhoven by Van Campen in the Netherlands

A new study conducted by researchers at the University of Michigan in Ann Arbor describes the origami inspired method.

The origami sonic barriers rely on cylinders called inclusions which are placed on an aluminium sheet bent into a Miura fold - an origami folding method which involves folding a flat surface, such as a piece of paper, into a small area - like an accordion.

As the resulting lattice fold, the cylinders are drawn closer together or farther apart, diffusing noise in different frequency ranges. 'The lattice contains only one degree of freedom, making it particularly easy to collapse and expand,' said Manoj Thota, a co-author of the study.

Manipulating such a lattice may allow traffic experts to adjust noise-dampening devices to particular frequency ranges.

For example, heavier vehicles produce noise at lower frequencies than lighter vehicles.

Cars traveling quickly during off-peak times skew toward higher frequencies than cars stuck in traffic jams.

While concrete walls that line some roadways are effective at reducing noise from a broad spectrum of sound frequencies, the wind they block can add unwanted force on their foundations, and the straight top edges leads to increases in the propagation of sounds across the barrier.
[...]

https://www.dailymail.co.uk/science...gami-concrete-barriers-lead-silent-roads.html

For some reason, can't post pics with the new forum software. Will find the originating study and link and discuss later. Be aware that this will do nothing for the fundamentals of 'rumble', but will do wonders in the audible spectrum.

Lots here:
https://www.google.ca/search?q=orig...9i61l2&client=ubuntu&sourceid=chrome&ie=UTF-8

 

[Neutrino]

I hope they accounted for these sound barriers being so close together! If not done right the sound can actually reflect off each side and amplify the noise.

Oh that would be hilarious because it's precisely the kind of thing I can see Metrolinx's incompetent contractors fucking up.

 

[steveintoronto]

Oh that would be hilarious because it's precisely the kind of thing I can see Metrolinx's incompetent contractors fucking up.

Agreed, save that it wouldn't be in the contractual execution stage, it's in the *design* stage the shortcoming exists. As soon as I glanced at that pic, I immediately saw the propensity for serious trouble. It's an *invitation* to acoustical resonant properties run amok.

Consider that all it takes is rubbing a quality resonance device, like a massive church bell, to excite it into resonance. Or quality wine glasses. Just rub the lip (no further comment on that...wine is fine)...energy is *waiting* to be excited if not already in that state. And running a piston (train) down a channel with such rigid walls will do exactly that. Think a tunnel minus one of the containment surfaces.

This is such an incredibly bad faux pas. Standard practice would be to pleat the walls in a zig-zag pattern, offset to each other by the ratio of the 3:4:5 Pythagorean relationship in as many planes as possible.

Oh Lordy, Lord...

 

[robmausser]

Agreed, save that it wouldn't be in the contractual execution stage, it's in the *design* stage the shortcoming exists. As soon as I glanced at that pic, I immediately saw the propensity for serious trouble. It's an *invitation* to acoustical resonant properties run amok.

Consider that all it takes is rubbing a quality resonance device, like a massive church bell, to excite it into resonance. Or quality wine glasses. Just rub the lip (no further comment on that...wine is fine)...energy is *waiting* to be excited if not already in that state. And running a piston (train) down a channel with such rigid walls will do exactly that. Think a tunnel minus one of the containment surfaces.

This is such an incredibly bad faux pas. Standard practice would be to pleat the walls in a zig-zag pattern, offset to each other by the ratio of the 3:4:5 Pythagorean relationship in as many planes as possible.

Oh Lordy, Lord...

While it is an issue, it can be mitigated by adding some acoustical sound absorbing/dispersing material to the existing wall.

However, the walls themselves should have been selected with this type of property in the first place. But its not like it is not something that can be added at a later date, if they turn out to be a problem. At additional cost of course.

Im sure Metrolinx avoided any zigzag pattern of the walls because they want to use 100% of this available corridor space... it looks like there is just barely enough room to fit in 3 tracks, for express service.

 

[steveintoronto]

I have to disagree on the amount of extra space needed. The efficacy of this compared to the 'Origami' system will be limited, but still a huge improvement over what apparently is being done in this instance. I've yet to delve on the "notching" (notch filters) I mentioned prior, it's a topic in itself, as it involves 'voicing' of wanted or unwanted sounds.

Railroad Barrier & Airport Noise Reduction
Rail Road Noise Barriers
As the demand for transit and freight rail service increases, unwanted rail noise is becoming a contested issue in communities across the country.

Whether it is the result of newly-installed lines or the expansion of existing lines, the increased noise emanating from rail traffic is a growing problem and our railroad noise barriers are the solution.

Our sound-absorptive noise barriers effectively provides noise reduction for:

Commuter Rail
Freight Rail
General Mass Transit
Railway Yards

https://www.soundfighter.com/applications/rail-and-airport/

The closer this is to the sound source, the greater the efficacy of absorption.

Even Mississauga's pathetic 'looks rather than function' rules require a degree of absorptive/diffusive factor:

Design Solutions
To minimize the blank flat surface, the noise
attenuation walls should be designed to incorporate
the following:
 Different textures with the use of patterns such
as ribbed pre-cast concrete panels;
 There should be no blank flat surfaces within the
first 2.0 m ( 6.5 ft.) of the height of a noise wall
measured from the base of the wall

http://www7.mississauga.ca/documents/pb/main/2015/FINALNoiseMay201402.pdf

FONOCON® sound resonator – acoustically effective cap
Sound-absorbent edges have been the subject of experiments for many decades. Forster has now pioneered a clear solution based on the law of physics and using an efficient combination of computer simulations and standardised experiments – the FONOCON– sound resonator. An acoustically effective cap optimised specifically for the noise spectrum of railways, the FONOCON can be used on existing as well as newly built noise barriers.

https://www.forster.at/en/noise-control/rail/

Ostensibly what's known as a 'tuned sound trap'...none of these come close to the Origami innovation, but all are far better than just concrete slats in stakes...

 

[steveintoronto]

it looks like there is just barely enough room to fit in 3 tracks, for express service.

There's no room there for a third track....but what there's *really* no room for is...catenary!

 

[timio]

Bramalea north parking lot

 

[TOareaFan]

Speaking of Bramalea, this person included me in their tweet (not sure why) question to GO:

https://twitter.com/x/status/1063063266203709440

And here is the answer they got:

https://twitter.com/x/status/1063065059226779648