Fleischmann 0-6-0 squeal

[Teditor]

I am servicing a Fleischmann HO Scale 0-6-0 steam locomotive, at higher speeds it starts to squeal, then slows down, reduce the throttle and the noise goes away and the engine smooths out and increases speed marginally, the locomotive is DC only, I have cleaned and lubed it as per my usual methods and am running it on rollers for testing, the result is the same in forward or reverse, wondering if it could just be the brushes.

Ted (Teditor) Freeman
From the Land Down Under
(I don't suspect being upside down here in Australia as the cause!)

[strummer]

Sorry I cannot help; hopefully someone who can will chime in soon...

Mark in Oregon

[peteski]

Not familiar with H0 locos, but generally the high pitch sounds are usually caused by the parts of the mechanism that rotate the fastest: motor shaft or worm shaft.  You mentioned that you oiled them so I would have expected the noise to cease.  But maybe either motor or worm bearings are so worn that they have too much play in them)?  Motor brushes?  I don't recall ever seeing them squealing, but since they rub against the commutator which also spins as fast as the motor shaft, I suppose they could be the cause of the noise.