Track ballast
01
轨道道碴, 铁路道碴
the layer of crushed stones or gravel placed under and around railway tracks to keep them in place and provide drainage
例子
The workers spread new track ballast along the railway line to make the tracks more stable.
工人们沿着铁路线铺设了新的道碴，以使轨道更加稳定。
Without track ballast, the train tracks would shift and become uneven over time.
没有轨道道碴，铁轨会随着时间的推移而移动并变得不平整。
