@Dolph posted:Thanks everyone, I think you are on to something with the brush plate hole. Brush wells were cleaned and I have tried both the original as well as brand-new replacement brushes and springs with no change in performance. I will investigate the plate more tonight but I bet that is it, I remember it looking like it had taken a lot of wear. BTW this is a #02689WX tender.
To confirm that a wobbly armature shaft flopping around in a loose hole is the cause of your problem, I would turn the power on with the motor on my work bench (using jumpers for center and outer rail) and gently apply a thumbnail in a lateral direction to the end of the shaft and listen and feel for the vibration and noise to improve.
I would also not rule out a problem with your whistle relay - best way to determine if it's a factor is to bypass it and wire the motor to run directly off AC.
I would also check that solder blob connection where the orange & white wires meet up - potential for cold solder there - easy way to find out is to run the whistle (as-is) for 10-15 seconds, then feel the solder blob connection for heat - there shouldn't be any, but if there is a bad connection there, it will easily burn your finger "probe", so be careful.
