Which statement best describes lubricant selection for bearings and gears in locomotives?

• A. Lubricants should be chosen based on price and availability only.
• B. Any lubricant can be used if labeled synthetic.
• C. Oils or greases selected per manual with correct viscosity and compatibility; avoid contamination.
• D. Lubricants are unnecessary for bearings and gears.

Answer: (C)

Lubricant selection for locomotive bearings and gears is all about following the manual’s specifications to pick oils or greases with the correct viscosity and proven compatibility with the materials and seals in the drivetrain, while also preventing contamination. The right viscosity ensures a stable lubrication film under the expected load, speed, and temperature, reducing wear and heat. Compatibility matters because wrong additives or base chemistries can react with seals, metals, or other lubricants, causing corrosion, thickening, or film breakdown. Keeping lubrication free of contaminants—dirt, moisture, or fuel residues—protects the film and prevents accelerated wear or gear damage. Prices or availability don’t guarantee the right performance, a lubricant labeled synthetic may not meet the required spec, and lubrication is essential for bearings and gears, not optional.