can anyone direct me to a sorce for bridges ; curved with a 22" radius ?
What you're looking for might be better classified as a viaduct... Curved bridges are a rarity in railroading, although they do exist.
What kind of bridge are you looking for?
One place to start would be to do a google image search for curved bridges to see what's out there in the real world, then you can figure out how to approach your bridge project from the most realistic means available.
Keystone Viaduct on the WM curves gracefully over a creek, a highway, and the B&O main line, which is under the truss section in the distance. While the box truss itself is straight, the beams that supported the track were built on a curve. You can see how it works in this aerial view.
Thomas Viaduct, on the B&O near Baltimore, is a stone viaduct built on a curve.There are plenty of other examples, but until we know a little more about the scene you're modeling, it's hard to direct you to solutions.
Lee
Route of the Alpha Jets www.wmrywesternlines.net
Except for masonry and cement bridges, curved bridges are made up of a series of straight bridges. Easiest to build are wooden trestles (scratchbuild from stripwood or build from a large kit) or a series of 30-foot deck girder bridges as produced by Micro Engineering Company.
Mark
For a longer bridge on a curve, just add more bridge sections with appropriate vertical support:
This example has a 30-foot (scale) MEW deck girder bridge on a 18-inch radius HOn3 curve.
Except for masonry and concrete arch bridges, most bridges aren't 'curved' per se, but a series of straight sections 'skewed' to allow curved track to be laid on them.
Here's an example of my Deer Creek Viaduct, which is made up of two Micro-Scale viaduct kits, but constructed on a 36" radius curve. It was done by shortening the inside girders and butting them together, then laying Sinohara 'bridge' track at a 36" radius curve on top.
Pardon the unfinished scenery in these shots--I'm still working on it.
Side view:
Hope this helps.
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!