New laboratory methodologies to analyse the top of rail friction modifier performance across different test scales

Abstract

Test methodologies originally developed for greases have been adapted to be used for top of rail friction modifiers (TORFMs). This has included: a small-scale benchtop tribometer to measure the tackiness of different TORFMs, attaching an applicator bar to a section of rail and rolling a scaled-wheel through the TORFM applied to the rail head to analyse the effect of different variables on pick-up, and applying TORFM to a full-scale test facility to analyse the scaling effects and the effect of slip, load and speed on pick-up. These methods can be used to measure the relative performance of different TORFMs with respect to how much product is picked up by the wheel. The results have shown that the relative ranking of different TORFMs is the same across the three test scales. This shows that these small-scale test methods that are more suitable for inclusion in test standards could be used to reduce the need for the more time-consuming and expensive larger scale tests, as the relative performance is the same.

Studying the transfer mechanisms of water based top-of-rail products in a wheel/rail interaction

“…14,16 While these studies give possible test approaches, the application process and properties for TOR products are very different to greases, so the findings cannot be transferred. One laboratory-based study has been carried out on TOR product pick-up, 17 but in this work, friction was not measured and mechanisms of pick-up/carry-down were not explored in detail. Recently field studies carried out have shown that TOR products do not appear to be carried down more than a few hundred metres on the rail 18,19 From this work, however, indications were that the product on the wheel could be effective for >3 km.…”