Hi everybody, I recently purchased a Bachmann Peter Witt trolley and was disappointed to find it did not like the 104mm Tomix tram track curves at all. It ran through them, but really slowed down and growled while doing so. I like to tinker with stuff, so I opened it up to see if it could be improved. The fix was to pop off the worm gear covers, and loosen up the clips that couple to the ball joint on the worm gear. I used a jewelers screwdriver, and gently pried back each prong. This results in a slightly looser fit on the ball, and just a tiny bit more freedom of movement. Now it runs through the 4 inch radius curves without a problem!