Black Residue on Monorail

Symptom

There is black residue on the top of the monorail.

Resolution

Black flecks on the monorail rail are normal. They are a combination of dirt, perspiration, molydisulfide (a lubricant from the plastic rollers) and a very small amount of the nylon plastic that the rollers are made of. These four components are subjected to the mechanical action of the rollers and can dry and harden on the rail.

To remove the black residue, clean the monorail.