# Pratt Truss Bridge for Iron Island RR



## dieseldude (Apr 21, 2009)

The time has finally come to replace the temporary double track bridge over the pond. As much as I'm going to miss the rustic look of unrealistic, out of scale 2 x 6 lumber, I'm sure it's for the better. Since the span is 5 feet long (in 1:1 scale, of course) and double track, I decided to go with a Pratt style curved top design. Here are a few shots of progress, so far..........




























-Kevin. 
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## Dick413 (Jan 7, 2008)

must say it is, looking good


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## dieseldude (Apr 21, 2009)

A little progress on a big bridge...



















Stay tuned.......

-Kevin. 




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## dieseldude (Apr 21, 2009)

Another step (or two) closer to completion.....










It's kinda starting to look like a bridge.


-Kevin. 


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## Dave Meashey (Jan 2, 2008)

Kevin;
It is really looking good. I have daydreamed about finding a large Erector set at an auction or yard sale, then using it for a large bridge, but yours looks a lot nicer. My idea would probably require frequent applications of Rustoleum to stay intact.

Best,
David Meashey


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## Larry Green (Jan 2, 2008)

Mmm? Do I see "milk crates" and aluminum window screen framing?? Great looking bridge! 

For a good source of neat aluminum structural shapes, check McMaster-Carr online. Look up: aluminum; shapes (tee, angle, channel. rectangular, etc.) 

Lots of small sizes suitable for our projects. Also, their shipping charges are amazingly low. 

Larry


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## cocobear1313 (Apr 27, 2012)

That is very cool! 

DJ


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## dieseldude (Apr 21, 2009)

Dave- Thanks! An erector set bridge would look great as well. You'd probably get some very realistic weathering by not protecting it with Rustoleum. 

Larry- Yep- milk crates and aluminum window screen framing. Definitely helps to keep the cost of the project reasonable. Thanks for the tip about McMaster-Carr. I'm not much of a metal worker, but with all the great shapes they offer, I might be tempted to try more projects. 


-Kevin.


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## dieseldude (Apr 21, 2009)

Thanks, DJ. 


-Kevin.


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## dieseldude (Apr 21, 2009)

Got some paint on the bridge. I used the Henry Ford theory- I can have any color I want..... as long as it's black. Kinda "ties" everything together..........










-Kevin. 
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## dieseldude (Apr 21, 2009)

Had a little time this weekend to make some walkways and railings. If you look real close, you can see me standing on the bridge in the lower right hand corner.....



















-Kevin.


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## Bob in Kalamazoo (Apr 2, 2009)

Kevin,
That is one fantastic bridge. I would love to be able to sit down with you and have you show me how you did it. 
Bob


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## Matt Vogt (Jan 2, 2008)

Excellent bridge, Kevin! And I love that it was economical to build. Nicely done! 

Matt


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## Torby (Jan 2, 2008)

You bolted it together with gusset plates? What's the bottom made of?


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## Jethro J. (Apr 4, 2012)

Kevin,
That came out great, nice work.








Jethro


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## Totalwrecker (Feb 26, 2009)

Posted By Torby on 19 Jun 2012 09:07 AM 
You bolted it together with gusset plates? What's the bottom made of? 
If you don't read the whole thread, you get to ask already answered questions...









Milk crates made the supreme sacrifice....









Imagine, caught by your own signature line... ha ha.

Happy Rails
John


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## dieseldude (Apr 21, 2009)

Thanks, everyone!!! 


-Kevin.


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## dieseldude (Apr 21, 2009)

I'll torture you all with one final bridge picture......










-Kevin.


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## Ron Hill (Sep 25, 2008)

Kevin, a couple of questions on a good looking bridge. I made a Pratt Truss Bridge for my layout but it was make out of styrene. Yours will hold up longer. How is the milk crates attached to the stringers along the bottom? And what is the cross members along the top and internal braces made from and attached to the aluminum framework? I do like your bridge because of the structural soundness no matter how long it sits outside. Mine has been outside for 3 years and it had to come into the shop for repairs and painting. Syrene works well outside as long as it is painted and protected from the elements. 
Ron


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## dieseldude (Apr 21, 2009)

Ron- Thanks! The milk crate is sandwiched between a piece of 90 degree aluminum angle on top and a piece of flat aluminum along the bottom (underneath the bridge). I originally wanted to use some aluminum channel, but the milk crate material isn't all the exact same thickness. Using this method, the tops will all line up perfectly for a flat roadbed. I drilled some holes and used some nuts and bolts to secure everything. In order to hide the fasteners, I made sure that they coincided with the gusset plates. The cross members along the top of the bridge were scavenged from an old fiberglass garden arbor that my neighbor was throwing out (sometimes I save the strangest things!). I don't know if they still make those types of arbors anymore, but the material is real user friendly. Especially since the angle where the two pieces cross was somewhat complex (I'm a bit mathematically challenged!) I was easily able to "eyeball" the angle by placing one piece over the other and file a groove halfway through each piece. While the rest of the bridge is held together with screws, nuts and bolts, those cross members are actually secured to the aluminum with Quick Grip adhesive. I hope this helps. 


-Kevin.


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## toddalin (Jan 4, 2008)

Very creative use of materials.


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## Nutz-n-Bolts (Aug 12, 2010)

That looks great ! and I love your methods. Thanks for you last post explaining how you assembled things. Very creative. It sure looks great in it's new home.


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## dieseldude (Apr 21, 2009)

Thanks, guys!!! 


-Kevin.


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