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Bridge from Roadbed?

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  • Member since
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  • From: Miles City, Montana
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Bridge from Roadbed?
Posted by FRRYKid on Friday, June 29, 2018 9:39 PM

This one may be slightly off the wall, but here goes: Has anyone ever built bridges using Ribbonrail's Upson Roadbed as the base? I am at the point of designing something as a duckunder to connect two sections from my current layout that I am reusing. (Due to a family situation, I need to move my layout.) The two sections in question weren't originally designed to be directly connected to each other. (There was a 4 foot section that was between them to connect them in a straight line and that section won't be used.) They will end up being connected at around a 90 degree angle probably using 2 additional sections of 22" R track (Two already are part of a crossing for a road) and it would also join a line of three turnouts. (One would be on the bridge, one would partially be on the bridge, and the third is completely on the second section.)

As usual, thank you for reading my post and for any assistance that can be provided.

"The only stupid question is the unasked question."
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Posted by SouthPenn on Sunday, July 01, 2018 7:11 PM

I've never used Ribbon Rail. But a drawing might help explain what you need and get more suggestions.

South Penn
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Posted by FRRYKid on Sunday, July 01, 2018 10:09 PM

I'm not exactly sure about drawing it, but I will try to describe it better. The sections would join at a 90 degree angle to each other. The pieces that would join the sections in question would be 2 22"R sections, a LH #6 and a RH #4. Part of one of the 22s, the other 22, the LH #6 and part of the #4 would be airborne as it were. (The #6 was originally on a section that will not be moving.) The two 22's would complete a quarter circle off a LH #4 turnout. (The other two form a road crossing.) It then connects to the #6. (The open side connects to the car ferry dock.) That then connects to the #4. (The open side connects to a yard track for the car ferry and the storage track for the idler cars and the engine.) I hope this gives a better description of what I'm looking at.

"The only stupid question is the unasked question."
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Posted by dknelson on Monday, July 02, 2018 10:57 AM

I have some of that Upson board roadbed.  I am not sure I understand what you are intending here either, but I can say that the stuff while reasonably rigid (compared to cork roadbed) is not meant to be self supporting.  It is still a paper based product and would warp/bend, probably rather quickly, without something underneath it.  But the something underneath it would not need to be particularly thick.  Tubular aluminum from K&S for example.

Dave Nelson

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Posted by FRRYKid on Monday, July 02, 2018 11:08 AM

dknelson

I have some of that Upson board roadbed.  ... I can say that the stuff while reasonably rigid (compared to cork roadbed) is not meant to be self supporting.  It is still a paper based product and would warp/bend, probably rather quickly, without something underneath it. 

That answers the question I had. The pictures that I saw let me to think they were a wood rather than paper. I think I will end up going with a different option, probably involving a coping or jig saw.

"The only stupid question is the unasked question."
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Posted by Track fiddler on Monday, July 02, 2018 10:07 PM

I guess without a picture or a drawing I don't know exactly what you're trying to do either. I do know 1/8" Masonite for N scale works very well for making girder plate bridges. 1/4" could be used for HO. Eventually you just put your ballast over it and you never see the masonite anyway. It's a good idea to seal both sides of the Masonite as moisture from ballast or humidity likes to leech in overtime. Micro Engineering sells girder plates for both N scale and HO. 

(edit) Masonite is very dense and very rigid especially after the girders are added. The curved bridge below would support my locomotives no problem without the under supports I will be adding.

 

The three-tier bridgespan to the right of the foam Viaduct that is not complete yet will later have steel supports added (styrene). I am thinking of removing the viaduct all together and adding more girders and supports to get the DM&IR look I want for a future scratch-built ore tipple.

The girders I used where from a couple sets of Kato girder bridges I cut apart but here is the Micro Engineering girder plates I spoke of.

Good luck with your project.

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Posted by bogp40 on Wednesday, July 04, 2018 7:44 AM

Are you using this as the base for a ballasted deck bridge? The stronger the material for the smallest thickness is what is reqired, especiall for longer spans. If it sufficient strength, it should work without issue.

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

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  • From: Miles City, Montana
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Posted by FRRYKid on Wednesday, July 04, 2018 6:00 PM

bogp40

Are you using this as the base for a ballasted deck bridge? The stronger the material for the smallest thickness is what is reqired, especiall for longer spans. If it sufficient strength, it should work without issue.

Yup, that is what I had in mind. I just don't know how strong the bedding I was looking at is as I have never even seen the material in person. Hence my question.

"The only stupid question is the unasked question."
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Posted by wjstix on Thursday, July 12, 2018 12:41 PM

I used Ribbonrail on my old layout, so used it for about 18 years or so. As noted, it is formed from Upsom board, which is basically pressed layers of paper. It isn't particularly strong, so if you're asking if you can use unsupported Ribbonrail for a 2-3' long bridge, or use it as the floor of a bridge with added sides (like a through girder bridge) the answer is no.

You might be able to use a 3' long piece of Bachmann E-Z track however, as the plastic sub-roadbed with the code 100 track is quite stiff. But if it were me I would still support it with something like say a 1" x 2" or 1" x 3" piece of lumber laid flat...especially if it would be separate pieces of track with turnouts etc.

Stix

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