@Greg J. Turinetti posted:Blue/Greenish color? That makes me think of a Stadium set. Do they have red roofs and truss rods? Are you sure about the 18" length?
I don't have any photos of a Stadium set that are my own. If you Google American Flyer Stadium Set several images will be available.
Northwoods Flyer
Edit: This is the best link that I can find
It still could be the Minuteman set also, as the OP describes the set as coming with a brass piper and the Stadium set came with a tri-valve engine. The Minuteman cars likely said American Flyer instead of President's Special.
I believe the Minuteman set would have only came with 3 cars.