Move Components of attached blueprint along spline

Development Programming & Scripting Blueprint
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1

Good morning,

My final target is to represent a P&F Conveyor inside Unreal Engine. (Something similar to this - YouTube).

At the moment I am struggling to move the cart (blueprint) along a spline, being attached to another blueprint.

Captura1b.png
https://forums.unrealengine.com/core/image/gif;base64
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Problem is that in curves the BP2 is behaving like this (what is logic, because it is attached to the BP1)

Captura4.PNG

I would need that the “wheels” of BP2 sticks to the spline.

With this logic the back trolley of BP2 start moving from the blueprint

Captura6.PNG

Result:

Captura6.PNG

Any idea, why it is start moving.

I am open for any proposal.

Thank you.