Reasons for HIGH LUBE OIL CONSUMPTION in HHP locos

HIGH LUBE OIL CONSUMPTION 
a) EXTERNAL LEAKAGES. 
b) ENGINE ADDITIONAL DRAIN DUMMY LEAKAGE. 
c) LEAKAGE IN LUBE OIL DRAIN PIPE. 
d) WORN OUT PISTON RINGS & VALVE GUIDES. 
e) MAIN LUBE OIL HEADER LEAKAGE. 
f) ENGINE BLOCK LEAKAGE. 
g) SUMP COVERS LEAKAGE.