Alan - Thanks. You did a great job of capturing the big grain elevator complex look.
Ed Kaz & Apple & Spud Line - I was going to wait and take a few pics as I completed the construction of the addition, but it is so simple that I can easily describe it.
I use 3 1/2" plastic PVC sewer piper from Home Depot or Menards for the silos. Make a jig and saw the pipe to exactly the same lengths, I cut mine at 14" tall. I cut a base of 1/8" Masonite and glue the pipes to it with construction adhesive. Cut a top for the silos of rigid illustration board using the same adhesive. You can also use Titebond or Gorilla glue for the top. I sprayed mine with flat off white paint to represent silos that are painted white but weathered. The structure is made of foamboard with wood bracing inside. I made my windows by using wood strips cut and fit into the openings but you could use plastic windows more easily.
Art