I'm not familiar with Breda personally, I don't think it is a brand found in the US, but I believe those are what is known as artillery tractors....used in WWII to move heavy artillery guns and other heavy equipment. I haven't seen anything civilian tractor from that era with tracks.
I think you will find more information looking at it from a military perspective. A quick google search again didn't yield much, but someone was mentioning Breda being Italian?