N scale trolley slipping

[Hiking Ed]

I've been HO model trains for over 25 years. Just added an N scale Bachmann trolley to enhance the look on the layout BUT the N scale trolley seems to be slipping and I can't figure out how to trouble shoot it. I have a video that I can send outside the post.
Any suggestions of what / where to look at?

[the Bach-man]

Dear Ed,
Sounds like a split gear.
IS it new?
Contact service to discuaa your options.
Thanks!
the Bach-man