Remixed in as much as I took the original and made one similar from scratch, but took the inspiration from http://www.thingiverse.com/thing:244430 This can be extended or compressed in sketchup easliy to make it however long you want it. It snaps securely over the track, but does cause it to stand off the surface a little. We typically play on carpeted floor so it does not matter. Including the .skp in case you want to modify it as well.