Yes, I was also suspended for half a month because of gear slippage. By accident, I found that the yellow 3069b was removed. The gear separation can be delayed a little and there is no sweeping gear sound. At this time, the track is just aligned and there is still a short period. Locked, the springs popped out and the train smoothly opened. The counterweight mechanism is not very sensitive. I just tried it and I can work with two 18mm steel balls.