I stumbled on a solution today.  If the rail slides out enough to clear the joiner, the small screwdriver trick works great.  The joiner is easily removed and you can then push the rail slowly and carefully back until it is flush with the roadbed.

I was having this problem today with a brand new nickel/silver turnout.  After much frustration and many dirty words, I found the problem.  As you come into the turnout from the single end, you first meet the movable points.  Continue toward the frog and you will find fixed rails in the shape of a V with the open end toward you.  In my case, one of these fixed rails did not align with the back side of the movable points.  When a wheel hit this, there would be an audible click and instant derailment.  A little careful adjusting with my needle nose pliers and no more problems!  I hope this is of help to you.

Thanks for all the help!  I didn't know about the Atlas Terminal joiners.  That will come in handy.

I need a way to remove these without breaking the plastic spikes near the joint.  Just pulling with pliers doesn't work.  Has anyone developed a procedure that works?