ABSTRACT
Traditional understanding is that, at low speeds, long and heavy freight trains “fall in” to the inside of curves due to cant excess and steep ascending grades, which leads to the wheels dragging on the low rail causing excessive curve resistance. We have recorded the tracking position and angle of attack of hundreds of thousands of freight wheelsets operating on grades around Sydney. The analysis of this data shows that the effect of speed (or cant deficiency/excess) and grade on wheel tracking position is small. Instead wheels run in the direction of the angle of attack; if the wheels are pointing to outside of the curve, they will track to the high rail and potentially flange, and if they are pointing to the inside of the curve then they will track to the low rail and potentially flange. This result emphasises the importance of proper wagon steering and the role of bogie warp resistance in achieving correct steering.
