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How Should I Insulate Bridge Guard Rails?

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  • Member since
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  • From: Summit NJ
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How Should I Insulate Bridge Guard Rails?
Posted by fkrall on Friday, November 30, 2012 7:57 AM

Any suggestions for insulating the "pointy ends" of Code 83 guard rails for my bridge?

I could, of course, position them so they don't touch, but that's not the way the modelers I admire in this forum have done it, and I don't want blaspheme to cost me my groupie status.

I've seen references to cutting plastic to size, but that seems tedious and time-consuming to me (but I'll certainly do it if that's the best solution).

Would coating the ends with CA, Sitx-All, or Pliobond insulate the joint?

Thanks.

Rick Krall

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Posted by Wazzzy on Friday, November 30, 2012 8:03 AM

Place the rails as desired and cut a gap near the tip in a straight section. fill with plastic and paint to match.

hoope this helps.

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Posted by richhotrain on Friday, November 30, 2012 8:13 AM

I agree with wazzzy, that is the most effective way to do it and still keep it prototypical.

Rich

Alton Junction

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Posted by zstripe on Friday, November 30, 2012 9:49 AM

If they are guard rails,why do the pointed ends have to be insulated???

Cheers,

Frank

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  • From: Weymouth, Ma.
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Posted by bogp40 on Friday, November 30, 2012 10:02 AM

zstripe

If they are guard rails,why do the pointed ends have to be insulated???

Cheers,

Frank

Any tight gauged wheelset or anything else that could bridge the gap between running rail and guard rail will cause a short. The insulation is just good insurance to prevent a problem.

Modeling B&O- Chessie  Bob K.  www.ssmrc.org

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Posted by zstripe on Friday, November 30, 2012 10:17 AM

bogp40

zstripe

If they are guard rails,why do the pointed ends have to be insulated???

Cheers,

Frank

Any tight gauged wheelset or anything else that could bridge the gap between running rail and guard rail will cause a short. The insulation is just good insurance to prevent a problem.

I agree with you on that, but the wheels have to be really far out of gauge for that to happen. On my to swing bridges and others on the layout they have close to a 1/4 inch gap between them...

Cheers,

Frank

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  • From: North Dakota
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Posted by BroadwayLion on Friday, November 30, 2012 10:55 AM

Modeling Clay.

Swipe some from the nearest 6 year old who leaves it lying around. (of go buy some if you do not have any 6 year olds handy) You can model it easily into a point and then paint it. The LION has been know to use it to fill holes and to fabricate other details.

ROAR

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

  • Member since
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  • From: Summit NJ
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Posted by fkrall on Friday, November 30, 2012 11:14 AM

Very helpful; thanks.  Either the styrene or modeling clay (ingenious!) will work for me.  As to the styrene, after thinking about it, I now realize I will have "Dremeled" the ends to flatten the insides to make the point, so I won't have to follow the Code 83 rail contours as I feared I might.  And I have some modeling clay from  a recent turntable project, so I have choices.  Choices are good.

Rick Krall

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  • From: Southwest US
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Posted by tomikawaTT on Friday, November 30, 2012 11:15 AM

bogp40

zstripe

If they are guard rails,why do the pointed ends have to be insulated???

Cheers,

Frank

Any tight gauged wheelset or anything else that could bridge the gap between running rail and guard rail will cause a short. The insulation is just good insurance to prevent a problem.

I'm with Frank, for two reasons:

  1. Bridge guard rails aren't like turnout guard rails.  They usually allow enough space for the entire wheel to fit between them and the running rail, not just the flange.
  2. The total guard rail assembly should be as electrically dead as the French monarchy.  If it isn't, find out why and correct.

Looking at a prototype photo of a long, high deck girder viaduct, the guard rails look like mine car rails and are only spiked every fifth tie!  Pretty obviously, they were never intended to support the triple-headed 2-8-2s blasting upgrade across that viaduct.  All they're supposed to do is keep a derailed wheel set on top of the ties - and the attached car/locomotive out of the gorge below.

Chuck (Modeling Central Japan in September, 1964 - with LOTS of guard rails)

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Posted by fkrall on Friday, November 30, 2012 11:23 AM

"...as electrically dead as the French monarchy."

Great line!

Rick Krall

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Posted by doctorwayne on Friday, November 30, 2012 12:13 PM

I've seen only a few instances where the guard rails touched one another, but as others have noted, there's plenty of clearance between them and the running rails.  Any wheel wide enough or that far out-of-gauge would have derailed long before reaching the bridge.

Here's a not-so-neat example:



Wayne

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Posted by selector on Friday, November 30, 2012 12:45 PM

There should be virtually no chance for a short if one metal wheel happens to touch the guard rail and the stock rail at the same time, even if the guards do touch at a pointy solid sharp end just off the bridge deck.  The reason is that the wheels are at a defined gauge, and therefore at a defined distance apart.  If one wheel slips between the guard and stock rails and rubs both at the same time, the wheel on the opposite end of the axle will be displaced the gauge distance.  There is nothing touching the guard and its counterpart nearer the opposite stock rail except the one wheel with electrical charge from only the one stock rail.

Otherwise, as the photos above show, guards have many endings.  They come pointed, dual-curved, and separated.  My photo here shows how I modelled one setup I saw personally.  I don't remember where it was, unfortunately.

Crandell

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Posted by fkrall on Friday, November 30, 2012 1:33 PM

Selector said:  "The reason is that the wheels are at a defined gauge, and therefore at a defined distance apart."

Boy, Selector, now that you mention it, that seems patently obvious to me.  But I didn't consider it before and confess I've never challenged what I believed was conventional wisdom that there's a risk of guard rails shorting.

Regardless, leaving them open solves the problem.  And to illustrate you've provided one of my favorite scenes on your layout, in fact the one on which I've based the abutment design for my bridge.  So I win twice!

Rick Krall

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  • From: Dearborn Station
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Posted by richhotrain on Friday, November 30, 2012 4:31 PM

selector

There should be virtually no chance for a short if one metal wheel happens to touch the guard rail and the stock rail at the same time, even if the guards do touch at a pointy solid sharp end just off the bridge deck.  The reason is that the wheels are at a defined gauge, and therefore at a defined distance apart.  If one wheel slips between the guard and stock rails and rubs both at the same time, the wheel on the opposite end of the axle will be displaced the gauge distance.  There is nothing touching the guard and its counterpart nearer the opposite stock rail except the one wheel with electrical charge from only the one stock rail.

Crandell, that would be true if the wheels move laterally in the event of a derailment, but if the trucks turn at an angle and the wheels are touching both the stock rail and the guard rail on each side of the track, a short will occur. The best practice is to somehow insulate or gap the rails.

Rich

Alton Junction

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Posted by doctorwayne on Friday, November 30, 2012 8:53 PM

richhotrain

Crandell, that would be true if the wheels move laterally in the event of a derailment, but if the trucks turn at an angle and the wheels are touching both the stock rail and the guard rail on each side of the track, a short will occur. The best practice is to somehow insulate or gap the rails.

Rich

Pretty crummy guard rails if they can't keep the wheels facing the proper direction, I'd say. LaughLaughLaugh

Wayne
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Posted by richhotrain on Saturday, December 1, 2012 4:35 AM

Let's look at this from another perspective - - - that of the manufacturer.

I have Walthers Shinohara Code 83 bridge track on several bridges on my layout.

If you look at the guard rails, they do not join together at either end.  There is a slight separation.  To complete the guard rail setup, there is plastic forming the V.  That plastic closure is colored brown so it doesn't look anything like the guard rails.

I assume that Walthers Shinohara chose not to join the rails to prevent shorts, however unlikely they might be to occur.

Rich

Alton Junction

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Posted by mobilman44 on Saturday, December 1, 2012 6:21 AM

Hi!

I must be missing the problem here..........  the guard rails  I am familiar with would just not cause a short, even if they touched a rail.

Of course that assumes the bridge/base is not metal..............

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

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Posted by doctorwayne on Saturday, December 1, 2012 11:33 AM

richhotrain

....If you look at the guard rails, they do not join together at either end.  There is a slight separation.  To complete the guard rail setup, there is plastic forming the V.  That plastic closure is colored brown so it doesn't look anything like the guard rails.....

Rich, you simply need to paint the plastic bits the same colour as the guard rails - rust or whatever colour you use. 
I can't imagine why this has cropped up as such a big issue - I don't think I've ever had a short on my layout in the 20-or-so years it's been in use, and even if I had, it wouldn't be a big deal.  Simply fix the rolling stock that's derailing and/or fix the cause of the derailments. Smile, Wink & Grin


Wayne

  • Member since
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  • From: Dearborn Station
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Posted by richhotrain on Saturday, December 1, 2012 11:56 AM

doctorwayne

richhotrain

....If you look at the guard rails, they do not join together at either end.  There is a slight separation.  To complete the guard rail setup, there is plastic forming the V.  That plastic closure is colored brown so it doesn't look anything like the guard rails.....

Rich, you simply need to paint the plastic bits the same colour as the guard rails - rust or whatever colour you use. 
I can't imagine why this has cropped up as such a big issue - I don't think I've ever had a short on my layout in the 20-or-so years it's been in use, and even if I had, it wouldn't be a big deal.  Simply fix the rolling stock that's derailing and/or fix the cause of the derailments. Smile, Wink & Grin


Wayne

LOL

That's not my point though, Wayne.

What I am saying is that Walthers Shinohara left the guard rails open rather than closed.  So, they were obviously trying to avoid the possibility of shorts.  Yet, they molded a plastic V-shaped closure to make it look more prototypical.  So, if you want to make the guard rails appear closed, just paint the plastic V to match.

Why has this cropped up to become such a big issue?  I don't think it has become a big issue.  It is just the typical thread with a lot of responses and a lot of opinions.    Angry

If I were handlaying my own bridge track, I would not close the guard rails simply because I would not want to invite the possibility of a short.  Having said that, I went down to my layout and tried to create a short, and it is nearly impossible, although it can occur.  

Rich  

Alton Junction

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