AAR M-914 paragraph 2.7.1 – Water Stability (American Association of Railroads Specification M-914 Brake Cylinder Lubricant Water Stability)
During normal operation brake cylinder lubricants may be exposed to environmental water. If the water causes a significant change to the grease consistency, the system may no longer be properly lubricated. This test determines changes in grease consistency (penetration values) when the lubricant is exposed to and mixed with water.
The prolonged worked penetration of the original test grease (ASTM D217) is determined. A second sample of the test grease is combined with water and the prolonged worked penetration of the mixture is determined. If the penetration value of the mixture vs the original grease is within the limits of the specification requirements, a “pass” is reported.