When I was young my brother and I had HO Train sets. My father had painstakingly built a large permant train layout with several sets of trains with buildings, trees, bridges, and the ground was painted and had mountains and rocks. I remember the curves in the tracks even had a slight grade on them. These were the most wonderful things in the world at the time! I am sure they are still (dismantled) in my dads attic! I bet they still work and they are about 40 years old. I had LONG Forgotten about them until your post.