Digging Into the Timeless Question, “Which Oil is Better?”

I would imagine that most people on here aren't aware that the railroad never changes the lube oil in a locomotive (unless it suffers a major engine failure)... and locomotive engines don't have oil filters either (FYI)

The railroads have special trucks with centrifuges on them that spin the lube oil to remove the suspended crud and then they add the depleted additives back in and put the oil back in the crankcase. Been that way for decades.