# Viaduct for Iron Island RR



## dieseldude (Apr 21, 2009)

Well, it's finally time to replace the "cinder block and 2 x 6" viaduct that has graced my layout over the past couple seasons. In the immortal words of Chico Marx, "Vi a duck, vi not a chicken?" Anyways, here's what I got, so far.......

I used some spare 2 inch blue foam for the basic form. I only have one 4 x 8 piece, but according to my calculations, it should work (please remember- I do all my calculations on my fingers and toes, so there are no guarantees). I need to span a distance of about 17 feet. I'll need to make two viaduct sections and place a bridge between them. I've already got the bridge, so that will save some work. 


I made a template out of some scrap luan to get the arches even. 









I used a Harbour Freight hot knife to cut the arches out. Really bad stinky smell of hot knife burning through the foam- wish you were here to get the full effect!!!










Here's one of the finished sections. I glued the parts together and then made some large wire staples for mechanical reinforcement. Mental note: Always read the entire label on the glue container!!! Some adhesives don't eat _foam_, but DO eat _*STYRO*_ FOAM!!! Luckily, I tried it on scrap, first! After the glue was dry, I cleaned and shaped up the under sides of the arches with a rasp. 



















Tune in next time for more fantastic foam adventures........... 

_-Kevin. _


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## tj-lee (Jan 2, 2008)

So far, so good! 

Best, 
TJ


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## fsfazekas (Feb 19, 2008)

Very nice, can't wait to see more...


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## wchasr (Jan 2, 2008)

Looking good so far! 

Chas


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## dieseldude (Apr 21, 2009)

Thanks, guys. 

-Kevin.


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## acmartina (Jan 6, 2008)

Hi Kevin,

Looks great. I have been putting off building a similar viaduct for several years. Maybe this will inspire me to get moving! I was a bit concerned about strength so was planning to use a sandwich of treated plywood and foam.

What are you planning to do for a coating? I was going to try what Rudy Allarde did on his roundhouse (http://www.mylargescale.com/Community/Forums/tabid/56/afv/topic/aff/7/aft/8802/Default.aspx).

Looking forward to seeing your progress! Thanks.

Steve


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## lownote (Jan 3, 2008)

That des look good. I think Jerry Barnes did something very similar, and he said it held up well although sometimes squirrels would take a bit out of it.


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## dieseldude (Apr 21, 2009)

Steve- I have some concerns about strength as well. I cut a couple of channels in the top of the viaduct and inserted some metal bars below the tracks for strength. The bars I used were actually some metal shelf supports that I had lying around. I have some pictures of my progress but, my CPU is DOA! It just died the other day and unfortunately, I am temporarily without a computer. I have had to use the library computer for now, but as soon as I get up and running again, I will post some more pictures. I think pictures would describe the self support idea better than words will. Until then........... 

-Kevin.


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## dieseldude (Apr 21, 2009)

Hey!!!! Remember me!?!! I know, its been a while since my last update, but I finally got a new computer and it's time once again for more high flying foam viaduct adventures!!!! As I mentioned in our last episode, I used some old metal shelf rails to add strength to the arches. I figured it would make more sense to show a picture than to try and explain it. I cut a groove in the top of the viaduct, just deep enough (about 1 inch) for the metal shelf rails to sit under the tracks. Since the depth of the arch is only a couple of inches, I made sure that the shelf rails extended the entire length of the viaduct. To give you a better idea of the type of shelf support I'm referring to, I left one on top of the viaduct (left side of tracks).










So far, so good....... or so I thought. At this point, I figured it would be a good idea to coat the entire structure with some hydraulic cement. I read Todd Brody's excellent article in Garden Railways and thought I'd give it a shot. I had some hydraulic cement. I got a cheap sifter and a spray bottle, and went to work. What could possibly go wrong? Of course I probably should have taken in to account that Todd's project was much smaller than mine. Apparently, even with the metal stiffeners embedded in the material, my behemoth seven foot long flying fortress of foam still had a wee bit of flex-appeal. You guessed it. After letting the the cement set up for a day or two, the structure still flexed enough when I tried to move it. CRACK!!!!!










Not to fear. Where there's a will, there's way. Just not really a way with hydraulic cement. Plan 'B.' I chipped off the remaining cement. Instead of hydraulic cement, I ended up painting the structure with UGL water proofing cement paint. The type you use for water proofing basement walls and masonry work. I use it all the time when I make foam foundations for my buildings. It worked out well.

Once the paint dried, it was installation time.










I thought I could finish up and install the viaduct and bridge all in one day. Mother nature thought otherwise and decided it would be a good day for some rain. Tune in next time for the big blockbuster finale (or as the Mrs. would say.... "Finally!").


_-Kevin._
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## tj-lee (Jan 2, 2008)

Kevin, 

That's a good looking viaduct! 

Best, 
TJ


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## jimtyp (Jan 2, 2008)

Great idea and thanks for the how to!


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## dieseldude (Apr 21, 2009)

Well.... Here it is....












All that's left to do is install some railings. I haven't decided what type of railings to place along the top sides. Either a basic post and railing or a more concrete looking railing. Perhaps that will wait until next season, as winter is vastly approaching!

-Kevin. 
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