GPTOM...
Try backing off the two screws on the top surface of the motor drive. For clarification, check the second (middle) photo above....there are four (4) screws on the top horizontal surface of the traversing unit. The two closest to the beam end....back those off about 1/4 turn and see if your problem improves/changes.
If I understand your problem description, you're losing your culvert on the way TO the car. I can't relate to that. All of my problems...and apparently John/Sean had the same...seemed to be regarding proper release of the culvert at the start of the return to 'home' position. Even there, I had a bit of residual variation between the plastic traversing motor drive and the sheet metal frames of the claw, which moves somewhat independently. Relaxing those two screws a mere 1/4 turn seemed to have a benefit in helping this, too.
(Update March 5, 2018: As it turns out my suggestion in the above two paragraphs is worthless and totally off the mark in retrospect!
See my entry below, same date, as to what REALLY improved the trolley motion!!!)
But, the biggest gain, far and away, was moving the micro switch mounting.
I've decided that this whole scenario is not unlike a lot of Lionel's accessories. There's always some improvement one can make resulting in more reliable operation. OTOH, sometimes the variation (Milkman throwing the milk cans out the door of the milk car, having them land helter-skelter......always good for smiles, giggles, laughs.
KD
