What's the real, the principal source of the characteristic 'grinding' noise from these ubiquitous 2-axle cars?
Put another way, what is the single most effective repair that would have these buggers ricochet back and forth down the track without sounding like they're trying to destroy themselves?
I've repaired several of these through the years. As per service/construction documents on these I've always taken care to be sure the parts are correct, complete, replaced as necessary. Each unit has been thoroughly and carefully cleaned...especially the commutator and brushes...then properly lubed during re-assembly. And they all have that characteristic grinding noise when they're tested.
What have the gurus found to be primary/secondary culprits for the noise? Inherent cogging of the motor by design? Axial play of the vertical shaft? Imprecise worm/gear mesh reflecting motor cogging? Sparking between the brush and commutator? Etc., etc., etc..? All of the above? And then some?
The #60 Trolley I just cleaned/repaired got me to wondering. When it was then tested, while running in one direction it was uncommonly quiet...IMHO from years of repairing/cleaning these..., but in the reverse direction it was more typically a real 'grinder'...and somewhat slower in speed. Clearly something was different about the motor/gear/everything else action in the two directions.
I've usually embraced the grinding sound of these beasties as part of the Lionel 'schtick' of this postwar genre. But, now this latest trolley has me wondering; Can that grinding noise...in BOTH directions...be better controlled by ___?__??
I guess I could carefully evaluate/alter some of the possible variables in the design to see their effects. But, hey...life's too short, and, more importantly, there are forumites far more invested in understanding these sorts of issues to 're-invent the wheel', so to speak.
Any thoughts to share?
And, no!...I'm not going to turn up the music and turn down the hearing aids!! And, to Homasote, or not, has nothing to do with the question or answer!
Thanks in advance.