Temperatures and wear at railway tread braking: Field experiments and simulations

Abstract

Field tests were carried out for a commuter train in revenue service equipped with cast iron and organic composite brake blocks. Temperatures for wheel tread, wheel web and brake blocks and wear of wheel treads and brake blocks were recorded. The measured temperatures are used for calibrating a thermal model for assessment of wheel and block temperatures. The wear of cast iron and organic composite brake blocks is estimated using simulated temperatures and temperature-dependent wear models based on pin-on-disc experiments. It is found that a wear rate adaption factor, tentatively motivated by the presence of thermoelastic instabilities at full-scale braking that cannot be found at small-scale testing, is required for producing a simulated wear that is in agreement with results from field tests. Wheel tread wear is assessed as change in flange height for both powered and trailing wheels and for the studied train it is found that the levels of annual total wear of these types of wheels are similar in magnitude. Modelling of the tread wear originating from block–wheel contact and wheel−rail contact, combined with a comparison with measured wear magnitudes, makes it possible to quantify the wear from these two tread contacts. It is found for the powered wheels that wear induced by the wheel-rail contact and the block-wheel contact have equal importance, whereas for the trailer wheels the wear emanating from the block-wheel contact is dominating.