Enough combinations later and I have finally found the right one to replicate the train.
I still don’t understand why this works… but it does, so… if you know, please explain it to me.
(everything i know screams use Authority not Remote… but this works and the other way makes duplicates for the client)
(seems adjusting the rotation to this fixed the issue of the client’s train constantly drifting negatively in the z axis)
At this point im wondering if I shouldn’t use the same sequence of: custom event > switch has authority (Remote) > Custom event (Server Only) > whatever logic… but if it works as it is I probably won’t. Client is very jittery in train but its passable.