Children's O scale train sets from Lionel come with a 40" by 60" oval of their FasTrack integrated roadbed track. An experienced N scaler on one of the big online forums asked what the exact dimensions were, because he's planning on buying a Lionel set for his son this coming Christmas and wants to build a table for it underneath his N scale layout. As space is one of my first concerns when giving model railroad trains to children, I don't usually recommend O scale trains for children. But I think this model railroader's idea is a wonderful solution to the issue of space for a child's train layout. I wish more children were so lucky.