Check around the shops that supply fake food for restaurants, ya know the plastic stuff in the windows? Japanese restaurants are very big on this. If you can find a supplier there, you can find lifelike plastic hamburgers, hot dogs, fries, etc, almost anything and use them as flatcar loads of the McExpress
Something that lots of stores do is buy on of the LGB F7 Clear Bodies and then put whatever decals you want on it. These engines are awesome. We ran them at Disney on our display for the Flower and Grden Show and people really liked them. The lights in the windshield and throughout the lenght of the engine are really cool. It is a “real” engine but is imaginary just as your freight is. Oh, and it goes around R1 turns.