Some trains must run on the same track. I was thinking of making my sister's in Law this type of thing for Christmas too. They travel a lot and I thought they would like something like this for their suitcases. I also was thinking of adding a zippered travel jewelry holder and a cosmetic bag to make a set of them.
The link doesn't show anything for free, but, the picture that is shown is enough for me to make them. I like the center flap that holds everything into place.