I took the original file (http://www.thingiverse.com/thing:295531) and changed multiple things to make it fit. I printed 2 of these at the meeting, and they both worked!
The "forks" (the part that breaks off and causes this mess) needed to be widened to go around the peg in the controller, and they needed to be positioned a little bit lower to properly fit it in the slot.
I also widened the side slots a bit because it took pressure to fit the cover down onto those little guide rails
Someone at the NMRA meeting also mentioned that the raised letters interfered with the battery when they tried this model, so I made the lettering recessed instead. (And yes, I left the logo alone. ASMR created 99% of this file, I just tweaked 3 or 4 dimensions to make it work. Hat tip.)
I'm sure that a few more refinements would make this an even better fit, but it just needed to work. Please tweak and modify to your heart's content.