Matt,
Monson #3 and #4 are two of the great Maine Two Foot relics. If you want to understand the whole story you need to find the book "Maine Two Footers" by Lynwood Moody. It is not the most detailed of the books but it is well told by a man who actually saw them all. He also was there when they set up Edaville and lead the hunt for equipment to save.
It was my introduction to the two footers years ago.