squealing loco's

[:D]Hey mrxr’s I got a [?] can you help me, I have a UP dash-8 and a SP GP40 that “squeal” when they run, I have cleaned the track and the copper connecters on the loco’s I have also cleaned lubed the motors,but they still squeal, what else can I do next [?]
Thanks for the Help[8D] TrainsRMe

I used to have an older Bachmann SP Daylight, and it would also squeal when running - at least for the first several minutes. I think it was the bearings for the axles. If you have lubed the motor already, you might try some grease on the axles and see if that helps.

Rob