Hi there, I'm writing a kids' book where a character hops into a freight train gondola full of scrap metal that's been rejected and is going back to a scrapyard. I was thinking the load might have been rejected because of contaminants, like oil tanks that hadn't been sufficiently cleaned of oil. But what would those oil tanks look like after being processed by the scrapyard? Would they just be in little pieces of metal? Or would there be large pieces moving around the train car?

Any help you could give is really appreciated! I'm also open to other suggestions of what might be in that freight car. The character in the story hops into the gondola because it's going to a scrapyard that's known as a shipper, not a receiver, but he's unpleasantly surprised to find that the gondola is actually full of metal because it's been rejected by the buyer and is going back to the scrapyard.

Thanks in advance.