Reference directed indexing: indexing scientific literature in the context of its use

In a preferred embodiment, the axle bearing caps of a railway locomotive traction motor include oil containing sumps from which lubricating oil is delivered by wick means to lubricate the axle-carrier motor support bearings. Overflow conduit means are provided which connect with an interior portion near the bottom of the sump and extend upwardly to an overflow outlet that is open to atmosphere and located at approximately the desired maximum oil level in the sump. When oil is added to the sump in excess of that required to reach the maximum level, the excess volume is forced from the bottom of the sump, out through the overflow conduit, thereby removing water and other contaminating liquids which are heavier than oil and settle to the bottom of the sump.