Do the research, never all that easy.

Last Thursday I stopped an Estate Sale. I don't like them if they are professional sales, but if the sign looks home made I'll stop in.

Large sale under several tents. They were selling all of Grandpa's stuff. They looked up most of the stuff on eBay and put crazy prices on the common items. I talked to the daughter who was running it and explained how you should go to advance search and only look at "sold" items to see what they are really selling for. She said she was wondering why sales were slow.
Anyway, there was a rusty cast iron item on the ground with $10 on it. I wasn't sure what it was. My first guess was a farm related item, but I couldn't figure it out. I asked her she said she didn't know either and everyone thought it a piece of farm equipment. I told her I'd buy it for five bucks just to find out what it was, she said sure and I bought it. At least 30 or 40 lbs.
Years ago I had worked in a rail yard and it looked like it might have been RR related to me.
Nothing like it on eBay, but did find one close to it on "image search", so here it is. An old RR car wheel break, most likely off of a lumber or log car.

https://www.dreamstime.com/royalty-free-stock-photos-wheel-brake-old-train-car-image25351778

No way to find a going price yet, so I'd be happy to sell it for $30. I'd bet some RR collector would love it for that price.