Several have suggested using the foamcore viaduct placeholder model as a base for the future "real" model. I honesty had not considered that, and I think it is a good idea. When it is time to upgrade the placeholder to the final model, I will certainly investigate it. I'm all for saving work if possible. In the future, the arch shape may not bother me so badly that I won't consider re-using it. Some styrene detail pieces, covering the foam edges, re-painting - it would look good. And because it is such an icon, I REALLY want it to look good. Thanks for the ideas.