I wrote an article that appeared in the March 2004 Railroad Model Craftsman titled, "Frugal Gourmet Modeling." The lead photo featured lasagna. I was creating a building under demolition scene and cutting up Evergreen strip to represent the debris was costing a fortune. I smashed up some uncooked lasagna noodles, painted them the same brick color as the building and added some weathering. Voila, unlimited construction debris for pennies. I just have to be careful that nobody spills a drink on it or I will have soggy noodles.
For your grated Parmesan cheese ballast you may want to look for very light yellow or cream colored aquarium sand. I used some aquarium sand on a project a long time ago and it was a bit messy to work with but it did come in a wide variety of colors.
Having grown up in Chicago where they eat "real" pizza (let the wars begin) you might want to consider a deep dish layout with the trains going through cuts and under highway bridges connecting the delicious pillows of Pizzeria Uno dough. Or Lou Malnati's if you are Ed K.
