Fence me in, please !

Construction fences are a mixed blessing. They are harbingers of something new, and hopefully improved. And they are less welcome when they block off public paths and spaces.

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Earlier this month the large parking lot on the north side of Albert just west of Bronson was fenced off. The parking lot isn’t much loss, but with it went Brickhill Street and a segment of Old Wellington, where the tour buses used to park. This will be a staging site for constructing the LRT tunnel under the downtown. So we are in for years of entertainment, err, mess and noise. Depending on your view.

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Earlier this week, crews began installing fencing just north of the Bayview Station. The former snow dump site off Bayview Road, known as Bayview Yards, and site of the former spay neuter clinic, will be a major staging site for the LRT construction project. This will include extending the Otrain track northwards … no, not to Gatineau, just a few metres north to better align with the future Bayview LRT station to be constructed above.

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I found myself wondering at the care to keep the fence off the rails, but then I thought  the rails are conductive, so maybe its to electrically isolate the fence from the rails, in case of lightning. Can you think of a better reason?

4 thoughts on “Fence me in, please !

  1. Re: the rail and the fencing

    It’s possible that that section of track is within the bounds of the signalling system. If so, it’s possible that a fence bridging the rails would complete a circuit and make the system think a train is present and in conflict with an O-Train leaving Bayview (even though the tracks were severed at the switch, the signalling system may not have been).

    That’s my guess, anyway.

  2. I think it is to make a fence that does not fall down.
    If you look at the lower image you can see that the section of fence that sits on the rails is unable to fully seat on the base that would normally support it (the base is near the right hand rail and shows two vertical prongs which slip into the hollow tubes that form the fence section perimeter). Since the fence sections will not fully seat on the base the fence will be unstable and liable to tip over.
    The wood on the rails is actually a fabricated inverted U which fits down over the rails. My bet is that we will see braces erected on these wood sections and these braces will slope up to the fence from either side in order to brace it and hold it in position.

    If the rails are cut then there should be no electrical conductivity and therefore no signalling. The signals still sitting further out towards the railway bridge are battered, broken and lack any visible power source.

    Aluminium on oxidized steel will not corrode very quickly in the absence of an electrolyte. Even if an electrolyte were present it would take an extended period of years to create visible corrosion and or weaken the fence structure.

    Does Commissioner street still go through or is that closed off as well? I’m curious about the track alignment just before the tunnel entrance. They cannot go too deep or they run the risk of flooding from the water viaduct. If the water level is the lower bound, I don’t think they can get under Commissioner St without some form of cut and cover work before the main tunnel entrance.

    1. “If the rails are cut then there should be no electrical conductivity and therefore no signalling.”

      Yes and no. Where the rails were cut was at the switch, but those rails would be in the next signalling block anyway. The rails in question would be in another signalling block, electrically separated from other blocks (if you look carefully, you can sometimes find non-conductive spacers in rail joints) so they could still send an “occupied” signal to the system, thus blocking the next block. Most railways these days have buried signalling lines running along them that don’t necessarily cease to function when the rails are cut.

      “The signals still sitting further out towards the railway bridge are battered, broken and lack any visible power source.”

      That’s true, but those signals are for entering the block in which the rails in question lie (if heading south), i.e. one block removed. At issue is whether the point at which the fence is located is tied into the signals at the switch from Bayview Station.

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