Good Day, I use Bachmann couplers throughout my rolling stock. However, most couplers have plastic wheels installed. Who makes metal wheels that fit Bachmann N Scale couplers? Thanks!

Good Day. I have a question about N Scale EZ mate magnet couplers. I was wondering if other people have experienced what I am trying to describe below.
My cars and engines use EZ Mate Couplers. I seem to have a common occurrence when trying to couple two cars together.
For whatever reason, cars will not couple.  The couple heights are the same and the couplers are new. For example, the couplers come in contact with one another and seem
to clasp, but when the engine pulls away, a car is left stranded and would not couple to another car. I would like to think since we are dealing with magnets that I would not have this problem.
The couplers/trucks on my cars are made up of roller bearing freight trucks, some friction bearing and some have the frame mounted EZ mate couplers. Any insight would be greatly appreciated and thank you for taking the time to read this.