I've noticed with Generations it is MUCH more difficult to place lots and/or move things. Did you bulldoze the junkyard first? Or maybe make a lot that will become the junkyard, assign it as junkyard, then place the new junkyard from a save file or the library? If the game has placed the standard 30x20 junkyard into a larger lot, (mine put it on a 40x40 lot), you can't just move it unless you move it onto the same size lot that has been designated junkyard.
What I do is make my lot where I want it. Designate it junkyard. Get the junkyard from the library and place it on the new lot. Bulldoze the old junkyard and redesignate the lot to residential or different community.
