The wheel flange wear is caused by the flange action of the wheel and rail, whereas the double-groove wear on tread may be mainly caused by the break shoe.
轮缘磨耗主要是轮轨相互作用的结果，而踏面上的凹槽磨耗可能主要由闸瓦制动引起。
2
At the base of the groove, there is a single or double diameter hole, providing a sound path through the panel.
在该基地的沟，有一个单人或双人直径孔，提供一个良好的道路通过小组。
3
By varying the groove spacing, the diameter of the single or double diameter hole, and the rear air cavity depth and content, one can obtain absorption over a wide variety of frequencies.