Bob2,
Thank you. These were adopted for a small fee from ebay. The calf is all metal and non powered. It appears to be the same make as the Cow. I was going to try to describe what was done to create the calf, but I think a picture with the truck removed will do a better job. Looks like some sort of filler was used to fill in the steps. I did not create this unit, I purchased it already modified along with the cab unit. You are correct when you say these are quite heavy, surprising for their size.
The plan is to fix what is wrong or missing, glaze the windows, touch up paint, add a wagon wheel and a working beacon as seen on the smaller pair in front. The drive was already redone by Jay, and quite nicely I might add. To quote one of my favorite movies, "he's very thorough."
