As John said, we have seen a few people on the form with this problem.
If these switches are new, return them for replacements, explaining the the non-derail feature is wired backwards. If the are too old to return, you will need to remove the back of the switch.
Attached is the Lionel wiring diagram for Fastrack switches. I marked the two wires that control the non-derail. The wire attached to the straight route should be blue and should go to pin 3 on the plug. The curved route is green, attached to pin 4. If this is not correct, pry up the rail tabs and swap the wires.
Let us know how you make out.
