Curved bridge/viaduct


P

phatpony

Member
I finaly started building my layout today. I have about half of the lower staging benchwork done and have to build my helix before I can start on the real fun stuff. I decided on making my layout with continuous running with a workable amount of switching, and with that I have a few different elevations on my trackage. Now to the question, My upper trackage will come over the top of where I exit my helix (tunnel portal) at an angle, on a curve. The radius is about 30". Is there a commercially available curved bridge or viaduct that is about 6" high with that radius. If not, what do you guys recommend? I am not afraid to attempt a scratch build, but I would rather not. Can some of the straight bridge spans be adapted to a curve somehow? I welcome any and all suggestions.

Glenn

p.s. oh yeah, before I forget, it's HO scale.:p
 
I'm not aware of a curved trestle or viaduct. I used a Micro Engineering tall viaduct kits and made it into a curved viaduct. All I did was build each of the segments and then mitered the inside of the curved edge of each segment. You have to use the same angle on each adjoining segment or they won't mate up. Then curve your track and attach it to the viaduct.

The attached picture doesn't really show the curve in the finished viaducts but there is a gentle 'S' curve in it.

David
 
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Hello and congrats on starting the layout, i have a Cambell scale models wood trestle kit, you have the option to build it straight Or curved, you get templates for the deck at various angles from straight to 18" to 30odd" radius
,not built it yet so can't say how big it will be, i recon on 6" -7" tall and 10" -12" long. I think you can get a Micro Engineering kit to fit curves.
 
ncng said:
I'm not aware of a curved trestle or viaduct. I used a Micro Engineering tall viaduct kits and made it into a curved viaduct. All I did was build each of the segments and then mitered the inside of the curved edge of each segment. You have to use the same angle on each adjoining segment or they won't mate up. Then curve your track and attach it to the viaduct.

The attached picture doesn't really show the curve in the finished viaducts but there is a gentle 'S' curve in it.

David
Click to expand...

Holy, it looks like you've been busy from the shots of the "room" with the blue walls!
 
ncng said:
I used a Micro Engineering tall viaduct kits and made it into a curved viaduct. All I did was build each of the segments and then mitered the inside of the curved edge of each segment.

David
Click to expand...

Very nice. I will need more curve, any idea how tight a radius I can get? Like I said, it is around 30". I thought the track was pretty much straight on those ME kits. Does it allow for movement, say, to put a curve in it?

Glenn
 
The Micro Engineering kits come with small segments of track that are in fact straight. You are not required to use them and in fact, I didn't. I hand layed the track on wooden ties.

You can make the deck as curved as you want. You just have to figure out how many degrees to cut the individual segments to get the curvature you want.

As I remember, the bridge segments that come with the tall viaducts are 50 scale feet long each. This equates to about 6.9" long. Using your 30" radius, each 50 scale foot segment will handle 13.1 degrees of 30" curvature. You would then miter the ends of each segment 6.6 degrees (rounded) to get your 30" curvature. This is half of the 13.1 degrees.

David
 
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