There is a trestle bridge I might buy instead of building one it is made my cambell scale model it is in the walthers 2008 N and Z scale book it is on page 237 it is the LOW CURVED TIMBER TRESTLE and I was wondering if anyone has one or knows anything about it I really want to know what the radius of the curve is. If you know anything about it would be great help if you could tell me. Thanks