Wheel wear losses from bogie rotation resistance, effects of cant and speed

摘要

Previous investigation on wheel wear losses from bogie rotation resistance have only considered as designed curve operations, with a small cant deficiency present in the curve design. Results in such curves show a relatively small increase in overall wheel and rail wear due to bogie rotation resistance. The bulk of increased wheel/rail wear is caused by rotation friction moments at the centre bearing, which are generated in the curve transition, being retained into the constant radius curve. Cant deficient design curves are shown to not retain the full rotational friction moment that is generated in curve transitions. The wear losses on individual wheelsets is shown to be greatly affected by bogie rotation resistance even when the total wheel/rail wear for the wagon is not greatly altered. The wheel/rail wear is best described by classifying curves by the number of wheelsets in flange contact with the high rail. The Queensland coal operations have proportionally much higher wear rate increases attributed to bogie rotation friction. Large reductions of wheel wear have been anecdotally report by QR rollingstock maintenance staff following the introduction of lubricating polymer centre bearing liners. Case study simulations show that the track's dominant tight curve is very sensitive to high centre bearing friction. The curves occur on a 1:50 grade for which loaded traffic is downhill at 40 kph compared to the empty traffic climbing at the speed limit of 60 kph. Hence these dominant downhill curves have a cant excess. Bogie rotation friction management is shown to be particularly important on rollingstock with low warp stiffness that operate through tighter curves at lower than the cant design speed. Such rollingstock will exhibit significantly shortened wheel maintenance cycle times due to high bogie rotation friction retained into the curve and high wheelset angles of attack seen on the leading bogie. Wear rates can become further accelerated due to the negative impact high angles of attack have on gauge face lubrication. Bogie warp and wheelset angles of attack retained in constant radius curves are affected by lateral forces such as coupler angling train forces.