Clip brushes wouldn't require 2 trains. The tracktrain entity allows them to by tied to it with normal brushes. But that's not the point. The train is supposed to have glass windows.
![:biggrin:](http://192.241.182.11/images/smilies/biggrin.png)
And making the windows larger does help a bit. However, when the train goes around a turn or gets trackswitched the glass gets a few degrees ahead into the turn, thus popping the windows sideways out of their frames. Maybe the train has to move at like 2 units per second for it to look right lol.