The full ride version of the physics cable car I built in Unreal 4.
The little spheres concept results in too many collision calculations that is why the wheels are flicking around.
In the next version I will simplify by using “tubes” of wire so that only two collision meshes are passing underneath the wheels at any given time.
I already tested that and it works a lot better. Wheels a lot more stable.
Keep in mind this is 200 year old cable car or something all rusted up in the game story.
So its o.k. if its very unstable 
The game project is here: http://escapefrommillstation.com/