Can anyone offer advice on setting up bridges (removing the foam below, butments, etc)? I have 2" foam serving as the sub-roadbed. Is 2" not enough depth for a suitable bridge? If not, how to create more depth? My train mentor gave me his scratchbuilt 15in HO scale railroad bridge. Ideally, I wanted to have the railroad bridge with a stream below. Folks would go fishing from near the bridge or stream.
I thought to create that scene near a corner of the layout to mimic trains "going beyond the layout." Problem is that I do't have enough room for a consist to clear the wye (one fork of the wye would go across the bridge). Should I still put the bridge there or have it lead from a yard onto the team track?
Best,
Lee
If no trains will be going below the bridge, 2" of height is fine, assuming it's a stream or something. A road would probably want more clearance for trucks and heavy equipment movements. If you have tracks running anywhere below the bridge you are contemplating using, you'll need an absolute minimum clearance of about 2.75", and even then a wreck crane will not be able to pass under it. That is measured from the tops of the rails below to the bottom edge of the item supporting the rails above, such as steel girders.
You will have to provide a ramp up to the bridge on each side if you can't currently dig down and provide some height relief for what passes under the bridge. If you had an inch of foam under the 2" stuff, you could carve out what is under the bridge. For example, if the rail bridge were actually an overpass, the cars could dip down below the bridge and then rise up again as happens in many prairie cities. IOW, what many modellers do to get clearances is rise a bit to keep the grade acceptable and usable, but also dip the roadway or tracks below to increase the vertical clearance.
You say you only want a stream, and won't ever have a track running along the banks right under the bridge? Then pare down the bridge supports and/or abutments until they fit. All bridges are custom designed for their location anyway, and yours should "fit" what terrain and bearing material existed at the time of construction.
If you have no practical ability to use the bridge as you planned previously, then your first suggestion is fine, although it will take some skill to scenic it so that it looks good, is visible, and seems to actually belong. For your other idea, what would it bridge? I can't visualize what you are imagining here.