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panamaniac · 10-21-2014, 12:36 PM

From today's e-Record:

Margaret Ave. bridge construction starts Monday

Construction on the new Margaret Avenue Bridge is set to begin on Monday according to the City of Kitchener. The work is expected to be completed by July 2015 and there will be access to all businesses in the area during this time. The bridge was closed in June 2013 after it was deemed unsafe.

The85 · 10-26-2014, 10:52 PM

One thing that has always puzzled me on this is that the Margaret Avenue bridge was rehabilitated in 2003 (according to this date stamp on the bridge railing - https://maps.google.ca/maps?ll=43.427492...6&t=h&z=11).

Don't you think the City and their engineers would have flagged these design issues then? It wasn't that long ago, and all that money spent on the rehab is now gone and worthless.

panamaniac · 10-26-2014, 10:56 PM

I don't think that the problem with the design was identified until after the bridge in Quebec collapsed a few years ago.

Markster · 10-27-2014, 03:34 PM

I just learned something fascinating about the new bridge:

In this document

Quote:• GO Transit's position is that the currently proposed bridge opening (2-track option) is

sufficient to meet their needs now and for the expansion to two-way all-day GO train service.
A copy of GO Transit's February 18, 2014 correspondence is included in Appendix B. This
position was confirmed in correspondence dated April 21, 2014 and June 12, 2014. It was
re-confirmed in teleconference with City staff on July 23, 2014.
• In recent discussions, GO Transit sees the current opening as having potential for three (3)
tracks. This would be accomplished by relaxing standards for horizontal clearances and
accepting any related impact to operability of the trains under the bridge.

So the new 2-track bridge, with some relaxing of standards, would in fact allow 3-tracks in a pinch.

JoeKW · (This post was last modified: 10-27-2014, 05:37 PM by JoeKW.)

Quote:This would be accomplished by relaxing standards for horizontal clearances and
accepting any related impact to operability of the trains under the bridge

Does that roughly mean that the trains would have to slow down a bit to go through it?

MacBerry · 10-27-2014, 05:53 PM

(10-27-2014, 05:36 PM)JoeKW Wrote:
Quote:This would be accomplished by relaxing standards for horizontal clearances and
accepting any related impact to operability of the trains under the bridge

Does that roughly mean that the trains would have to slow down a bit to go through it?

Kitchener bound trains would be slowing as they approach the Margaret Ave. bridge site because the old station is only <500 m away and the new station will be about 1 km from the bridge. The reverse is true leaving for the Toronto run. There are two signal regulated crossings between the bridge and the new station location and so a limited speed would be specified by GO or the federal transport regulator.

There are maximum speeds GO would consider appropriate in a station approach/leaving but I can't find them online.

JoeKW · 10-27-2014, 07:11 PM

Right, I assumed that, but what does "and accepting any related impact to operability of the trains under the bridge" mean?

Markster · 10-28-2014, 12:45 PM

I suspect that there would be relatively technical limitations that us lay-people wouldn't quite get.

Potential problems I can imagine, from fitting 3 tracks under a 2-track bridge:
*) Less leeway for sway of the trains. This might limit kinds of cars allowed to pass at the bridge.
*) Rails may have a slight bend towards each other, to run under the bridge, limiting speed.
*) No buffer under bridge for derailment. Any derailment would likely hit the pier, and cause substantial damage.

These are entirely amateur guesses.