I am working on a lionel locomotive # 6 --4-4-0. I have cleaned the commutator and the brush tubes, dressed the ends of the copper gauze brushes, oiled and lubricated all moving parts. It is very sluggish and will not move under its own weight. The motor turns somewhat hesitantly when upside down and power is applied. Granted it is around 100 years old.
I have wondered if new, possibly carbon brushes would help; although they would most likely foul the commutator quickly.
Any suggestions would be appreciated.