UBC Theses and Dissertations
Understanding the wheel/rail transfer mechanism in liquid friction modifier carry-down Hibbert, Morgan John Edwin
In the rail road industry liquid friction modifiers (LFM’s) are used on the top of rail (TOR) between the wheel/rail interface to reduce curve noise, lateral forces, rail wear and fuel consumption. The friction modifier may be applied to the rail via a track side applicator and is carried down by the train into curved sections of the track where the greatest benefit is seen. A custom laboratory scale machine was designed and built for the purpose of conducting experiments to study the behaviour of LFM carry-down over a large number of wheel/rail interactions. The machine was also designed so that the film transfer at the wheel/rail interaction location could be studied. The use of a fluorescent agent to enhance the ability to visualize LFM carry-down showed promising results, enabling small amounts of carry-down that couldn’t otherwise be seen under ambient light conditions to now be seen under fluorescence. Qualitative experiments using the machine were performed showing that an increase in the wheel speed results in an increase in the amount of friction modifier transferred from the rail to the wheel at the initial pickup location, thus increasing the carry-down. Increasing the applied load had the opposite effect and reduced the amount of friction modifier initially transferred from the rail to the wheel, and thus reducing the carry-down. The profile of the wheel was observed to effect the initial transfer amount and the ensuing carry-down due to high/low pressure zones along the wheel/rail interface.
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