Two friends take the same train to meet. That would casuality.
Two friends agreed to meet at the station are. That's causality.
In the first case, nor friends and remembered each other, there was no plan to meet.
In the second case, the friends agreed to meet after a long time without seeing.
If slowly reread the two most cases, we note that in the second case there was also a casual component. One of the friends remembered the other, sought telephone number or otherwise agreed to meet.
Last of all, I think that behind causality, reviewing, we find a casuality.
So Causality and Casuality, always go together.
