How important is the specific type of oil used to lubricate these brass/babbit bearings? I know journal oil is the usual, but I operate very large water pumps at work that have similar size and type of babbit bearing and they have always used an R&O 68 type hydraulic oil which is much lighter weight. The only difference is the water pumps have direct lubrication without the use of wicks found in the traction motor set-up. Wouldn't the lighter oil be soaked up easier by the wick in the traction motor bearing therefore providing good lubrication?
Rich

I don't know that much about specific oils. However, I do know that rpm is of serious consideration when talking about lubrication of plain bearings. The right viscosicty is important to get the 'oil wedge', and rpm of the bearing will play a factor in this.

The other consideration for suspension bearing oil is the additives. Specifically the rust inhibitor. You want some form of rust prevention in that type of bearing. The problem is when they sit, not turning, if there is a drop of moisture on the surface it will make a rust pit causing problems later. If you choose an oil that meets the viscosity and rust inhibiting qualities, you shouldn't have any problems. Of course keeping the water out is more important, but that is tough in the case of traction motors. I know our deep snow seems to find it's way in once and a while!