Train System Causing Train To Glitch

could anyone take a look at my system and possibly help me with figuring out why my train train is flinging its self?

train test.rbxm (52.3 KB)

I have resolved this first issue, however I’m now having an issue with linking two ballconstraints to weld two cabs together. how can i fix this?

train test.rbxm (46.9 KB)