More input voltage probably wouldn't hurt. With those Pullmor-motored Hudsons, you really want the voltage at the rails to be close to 18V as you can get. The old conventional versions were rated for 20V. The motor can take it, but the TMCC circuitry is limited to 19.
Also since it is a series motor, it will slow down when it encounters increased load. Cleaning the track is always a good move, but I would suspect things like a loose track joint, a "pinch point" in the gauge, or your table isn't level in that location. Put a level on it (a short one maybe 6-12" long.) Another way to test for increased load would be with an AC ammeter.
If the platform surface has sagged between joists, sometimes putting shims under the legs won't solve the problem. More track voltage and/or a lower gear ratio would though. A true champion can win under any conditions!
