My son wants me to put my trains up, the only problem with this is that it would have to go on his bedroom floor. The floor does have tight pile carpet and I am wondering if the older O27 track could withstand getting stepped on from time to time (we all know how kids are). I want to put it around the perimeter of his room so most of it will be out of the way. Just what is going to be under the door at the entrance. Thank you in advance, Matt M.