I collect track planning and design books and have quite a collection. It starts way back when I was seven years old and a teacher gave me a copy of 101 Track Plans that she had taken from another student. The book is 40 years old now and I do have an updated copy, but still use this one as it has my notes and modifications in it. With that I have another 50 or so books. They come in handy for ideas, but now I have 75 years of Model Railroader on DVD so I can just use that for track plans.