Hi - first time poster, first time Lionel train owner, and feeling like an idiot at the moment.

My kids recently got the Hogwarts Express I train set (Lionel 7-11981), and I had to take the bottom apart to fix an issue with the wheels. However, I don't know how to put it back together. A white piece popped out, and I couldn't tell where it had originally been.

If anyone could be of help on how to reassemble it and what goes where (particularly the white piece with the screw through it), I'd greatly appreciate it.



Thanks!