Yeah...so...I wasn't giving it enough time to react to inputs. The controls are working properly. That being said, the far side of the gantry didn't want to move at all. With a lot of CRC 336 and some gentle (really, gentle) persuasion from a rubber mallet, I got it to move a bit, and proceeded to clean the track with 0000 steel wool, being very careful to clean everything off thoroughly. I suspect moisture was in there from the last time it was used, which was probably a couple years ago.

Now, on to get the Flexcut wired up and give it a spin!