I just started to build an N-Scale layout with Unitrack. I love the Unitrack, it works great. I'd like some ides for securing it to my foam board without glue. It doesn't seem like glue would work well, since it is basically hollow under the unitrack. Is there another way to fasten it to foamboard? I see some holes on the bottom, but there is no place to put a nail through on top!