Has anyone seen a listing of pre-built or even kit bridges available for O gauge? I don't even understand the various lionel options. I have these two "steel truss" bridges from Lionel with lights on top. There is no model number on them, just "Lionel Mt. Clements, Michigan" stamped into the deck. These have flat tops (not arched). I pikced up some used bridges and piers from a Forum member and one of the item,s looks like another one of these bridges. But when it got here, it had a curved arch top and was stamped "Model 321" and no light on top.
How many bridge variations did Lionel make? Has anyone seen any kind of index to them? I was wanting to do some kit-bashing from identical model bridges and now I am on shaky ground. Plus I'd like to know what my other options might be that I don't know about.