Quote Originally Posted by TonyP View Post
I've changed out wheels where the bearing got so hot that the outer race was split open and fused to the adapter and the rollers were falling out.

And before roller bearings they were babbitt bearings topped with brass. The thieves would hit a cut of cars sitting on a siding and with makeshift levers lift the bearing box enough to knock the brass bearing out with a bar. The good ones could get a string on cars and if the cars were moved every wheel needed changing. They got hot fast. Moved far enough and the axle end, where the bearing was supposed to be , would wear away till it was gone.
I was a submarine electrician and we changed out bearings because they all had resistance temperature detectors that were wired. High speed steam turbines had journal and thrust bearings, and motors had ball bearings. Wiped bearings were very rare, but many hours of work to replace. Submarines had two turbines driving one reduction gear so we'd have to disconnect the turbine with the bad bearing to restore propulsion. No roller bearings, they were too noisy.