If you are dead set on making your own or buying some ready made check out what I use in This Thread If you really want to make them and they are for the Thomas/Trackmaster/Tomy/Plarail type maybe you could try to design something like them. Only takes 2 scews at the top but for extra security what I did was buy the heavy duty picture hanging velcro strips from Command Strips to hold the unit snug to the wall on the lower portion. What I like about these shelf units is that they have a groove in them to hold the trains in place and they don't stick out from the wall very much to prevent any one from banging their head on them.
If you are not familiar with the 3M Command Strip line they are an awesome invention that lets you hang anything permanently but if you want to remove them they come off easily without damaging the wals. They can also be repositioned which makes picture hanging great when at first it looks crooked.
http://www.amazon.com/Command-Large-Pict...B00404YKZI
If you are not familiar with the 3M Command Strip line they are an awesome invention that lets you hang anything permanently but if you want to remove them they come off easily without damaging the wals. They can also be repositioned which makes picture hanging great when at first it looks crooked.
http://www.amazon.com/Command-Large-Pict...B00404YKZI