# Short Curved Bridges



## docwatsonva (Jan 2, 2008)

I'm in the process of building my new layout. It will have 3 separate lines. The outermost, mainline will have 10 ft. radius curves. In one corner, I will have a shallow gorge that will serve to drain the layout. The gorge will need 3, 2'-3' curved spans to cross the gorge next to each other but separated far enough to eliminate a single bridge option. The gorge is only about 10 inches deep. Since these will all be 10' radius, does anyone have suggestions on what kind of bridges I should use? I thought of Metal Garden's girder bridges but I don't think they're wide enough to handle the curved track. 

Any help would be appreciated. 

Doc


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## Richard Smith (Jan 2, 2008)

Doc, 

One advantage of a deck girder bridge is you can make your own deck as wide as you want. Buy just the bridge(s) without the plastic decks and build your own to the width needed to accomodate the track curve. I made my own deck from cedar all pin nailed together and then glued it in place on top as well as securing it to the approach trestlework (you could attach to the abutments in your case). Mine isn't curved but the idea is the same.


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## astrayelmgod (Jan 2, 2008)

I have a curved pony truss bridge, about 2 feet long on a 5 foot radius curve. It works, but it wound up being nearly three times as wide as a straight bridge. It looks rather seriously ridiculous. Luckily, it is way at the back, and few but me will ever see it. Can you redesign your drainage to come out at a straight section of track? 

Depending on what era you are modeling, you might consider a trestle instead. Curved trestles look great, and are even more interesting than straight ones.


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## pimanjc (Jan 2, 2008)

Unless you are modeling a modern era, a trestle might be considered. 
JimC.


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## docwatsonva (Jan 2, 2008)

Thanks for your input. It took a while to get a couple of shots of the area where I plan to put my bridges. As usual, pictures are worth thousands of words. 

Here are 2 shots from different angles. 



















Two comments: 

1. I guess I should have put my layout drainage area where the track would be straight. However, that's the lowest point on the layout. 

2. The 3 tracks are too close together to allow for trestles. which I would have preferred. 

I guess I'll have to build my own (3) girder bridges to span the gulley. Right now I'm considering 1 1/2" x 1 1/2" aluminum channel cut and bent at a couple of places to accomodate the 10 ft. radius curve. 

Thanks again. 

Doc


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## Rookwood Central (Jan 2, 2008)

Another suggestion would be to use a Culvert, using two or three two inch drainage pipes to carry the water under the track, and using concrete to create the culvert, these types are very common on our Australian Railways. 

I consider these tracks are too close together to have individual bridges.


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## imrnjr (Jan 2, 2008)

I got a curved deck girder from Eaglewings Ironcraft and it is top drawer! I just told the folks there what the radius and length was and the track type and... presto it's a fit! 










Now I'm thinking about adding Garden Metal models catwalk ties, but have not yet decided./DesktopModules/NTForums/themes/mls/emoticons/unsure.gif 

The bridge is a 36" straight plus a 16" 6.5'diameter curve, in two pieces bolted together and anchored at the far ends. It is solid as a rock at that length so I don't think what your considering would be a problem. 

My guess is that yours could be one piece for each track, and anchored on a continuous abutment at each end would look pretty cool! 

Good luck what ever you decide.. 

Mark


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## toddalin (Jan 4, 2008)

I recently needed to replace a short (~2ft) curved bridge and wanted something that would look good, but was cheap, quick, easy, and different than any of my other bridges on the layout. 

I know that wood warps and doesn't last (hence the replacement), and metal tends to rust, but styrofoam will be here long after we're all dead and gone. 

I had remenants of a large sheet of 1" thick that I bought to package some speakers for shipping. I was able to lay the track on the sheet and trace around it on the styrofoam to the desired width for the deck. I cut this out with a utility knife. The cut edge doesn't need to be perfect. It is covered in the next step. 

I then cut some styrofoam strips that were about ~1-3/4" x 1" and glued these around the sides so they stuck up ~3/4" from the "deck." 

For supports I simply cut rectangles of the appropriate length and width, again using the 1" sheet. I glued these to the bottom of the deck in the appropriate areas. I then used a file and sand paper to add a nice curve to the bottom of the deck between the supports. (Two inch thick styrofoam would yield a more beautiful, prototypical curvature for the bottom while leaving more thickness in the middle for support.) 

I then coated the structure with DryLock hydraulic cement. This goes on with a thick, milk shake consistency and you only have a few minutes to work with it so do small areas at a time. When it drys, it looks exactly like real cement and is totally waterproof (not that the styrofoam much cares). 

I put the bridge in place and the track was a perfect fit. The ~3/4" "side rails" that stick up are perfect to hold the ballast in place but are well under any trains. 

Sorry no pics of this one yet.


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## R.W. Marty (Jan 2, 2008)

Hi Doc, 
I'm with Rockwood on this one. 
Consider stone, concrete, etc walls and culverts with infill for all three tracks to pass on a common grade. 
probably better looking than three bridges that close together. 

A length of 4"round pvc sewer line tripled up would probably pass all the water needed to drain your layout unless your in a monsoonal climate. 
Just my thoughts 
Rick Marty


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## Duncan (Jan 2, 2008)

I third the motion for culverts. 
Easy to do, and three pieces of 2.5" ABS pipe will handle all the water you could put in there... 
Ain't nuthin' gonna put down so much water that it wouldn't drain out. 
'Cept amaybe a Cattergory 5 hurry-cane. 
But yer screwed then, anyway... 

Otherwise, I'd go with a triple wide trestle. Your depth isn't too much for that (and they still use trestles of sorts in modern day stuff, JC...)


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## docwatsonva (Jan 2, 2008)

Thanks for your suggestions guys. I guess I never thought of a culvert. I was focused on bridges from the get-go. I've actually started working on an aluminum angle-based bridge. Making one is OK but three of them sounds like too much work what with all the other stuff I got to do to get my railroad up and running. 

The height from the base of the drainage to the top of the final layer of ballast is only about 6 inches. A couple of 3-4" pvc pipes just might do the trick. I can go ahead and lay the pipes, backfill for the tracks and use some 1" foam for a temporary culvert. I can come back later and build me a nice, permanent culvert at on end. 

How's that sound? 

Doc


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## Duncan (Jan 2, 2008)

Doc, 
Use ABS pipe... 
It's UV impervious (unlike PVC), and cutting it on an angle sort of approximates (from The Department of Redundancy Elimination Department) the look of the real thing... 
I've got some pictures somewhere, and will try to remeber to find them/post them of what Ralph & I have done.


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## docwatsonva (Jan 2, 2008)

Thanks Duncan. Looking forward to the pictures. 

Doc


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## Duncan (Jan 2, 2008)

Doc, 
Here's a couple of shots of one of the culverts we've got going for flood control. 
This one has "open" ends, where most of te others have some bigger rocks stacked over the openings. 
Enough space is available between the rocks for the water to flow through... 



















Hope it gives you some ideas...


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## docwatsonva (Jan 2, 2008)

Thanks for posting the pictures Duncan. I'm going to be gone, on vacation, for a couple of weeks. When I get back, I'll head over to HD and get some ABS and give it a try. I think a double 3-4" culvert will do the trick. 

Doc


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