Thanks Robert. Yes, I know locomotive crankcase oil wasn't changed out completely very often, like it is in an automobile. The way it was explained to me one day when I caught a hostler job off the extra board during my UP days is that at some maintenance intervals, locomotives will have part of the oil drained down to a predetermined level, then topped off with fresh oil. This was from a backshop foreman I was working with that day. I don't know if he was yanking my chain or not, but that's how it was explained to me.

Even if that is true, it's safe to assume that it wouldn't result in a reliable enough waste oil supply to be recycled regularly for other uses except from all but the largest servicing facilities, which Portola definitely was not. Stockton was pretty big though, so I wasn't sure what to think.

Thanks everyone for all the information. Makes much more sense now.

Mike

Mike --

I've heard that process referred to a as "sweetening" the oil.

As for using crankcase oil in plain bearings, it seems to me there might be all sorts of contaminants in it, including water and tiny bits of bearings, neither of which would be very healthy for a bearing.