I've laid tracks, but I am not allowed to put an engine on them, nor wagons. I've used a road (the one that is black) on either side of the track; engines and wagons tolerate that, but since I also used that road to colour the tracks, it's a no go. Is the road added on top of the tracks my mistake here, or are the tracks not accepting placement of train parts? Or both?!! Whatever, this is a beautiful set and I'm enjoying working with it :)