A formal archaeological dig would be a great thing to do. (Is there any risk of the property being redeveloped in the future? It's prime waterfront land after all.)
When the SR&RL was being scrapped, various small items of railroad property without scrap value were reportedly dumped in the Phillips turntable pit before it was filled in, and I can imagine something similar happened in Wiscasset.
There could be some really interesting artifacts buried there!