These are my own creation. I was trying to replicate roller bearing trucks before Aristo-Craft came out with theirs. #1 is a LGB, #2 is a USA, #3 is Aristo-Craft, #4 is an unknown brand. The 3 axle is an Aristo-Craft from a heavyweight passenger car. I didn't finish it. Included are the screws to finish it. I think they look pretty authentic. You could use them as a prototype and make more of them yourself. With the Aristo-Craft ones going for $50-$75 a pair I would guess these could b...e made for under $25.
These are from my personal collection that I am downsizing. I will combine shipping on multiple auction wins.