Tom,
I would say the survey would need to separate, Accessories, Engines (Steam, Diesel), Freight & Passenger cars.
It would be hard to implement a system with a number of votes because the quantity you would buy would be price dependent. Likewise the Flyer chief vs Legacy would also be a problem. I have to give this some more thought.
Maybe I have to provide an estimated price for each item.
—Rocco—