oh, ok, it may just be because im stupid like many people know already.
Well, you can download the NL toolbox here at
http://www.coastersims.com/tia/toolbox.htm
when you get that up and running and stuff do this:
1. open your track file.
2. On the left hand menu there will be a list of stuff you can do with your track, somewhere near the top it'll say "Remove Data", Click it.
3. When the list shows up where you can check and uncheck stuff, check "3D Objects"
4. On the bottom click "Remove Selected Data"
5. Click the save option, then save it (obviously thats what you do)
6. Exit out of the toolbox if you would like to
7. That should be it and it SHOULD work