Here's a Fastrack layout that should work - the outer loop is O-72 and the inner loop is O-48 and O-36. All switches are O-72.
The second pdf lists the track pieces. May not be exact, but it looks pretty close. Note there are 4 spots where the track doesn't perfectly line up. It seemed to me that there are enough other pieces attached that the small discrepancies could be overcome with just pulling the pieces together. Have fun!
