For dads or granddads out there who gets involved in playing with "lego" I have just heard of a site in the U.S.A. that make realistic railway wheels to fit "Lego" There are various sizes and colours, with and without flanges, and holes for crank pins. I expect I will get loads of people telling me that every body knows of this company, but anyway they are, at http://www.bigbenbricks.com Look under Products. Also see the gallery. A lot of the models are American, obviously, but not all, and they are very good considering what they are made from.