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/